SANUR PTY LTD and CITY OF SUBIACO [2025] WASAT 107 | Case summary

SANUR PTY LTD and CITY OF SUBIACO [2025] WASAT 107 | Case summary | Zoe

[4]

Due to major trench excavations by public agencies on the adjacent footpath, substantial cracking appeared in the Building's dividing walls in the late 1980s. The Pritchard & Francis Report noted the significance of '... cracks in the wall above the ceiling line which are more like gaps (i.e. 50 mm or 2 inches wide)' and ultimately concluded that the cracks were not new, but old cracks which had re-opened.[10]
The Pritchard & Francis Report then noted that cracking in the walls was typically associated with differential settlement. The dividing walls, although supported by poor ground conditions, are unlikely to crack and settle differentially as a result of their own weight, or that of the roof. However, the front parapet wall (weighing approximately 10 tonnes per pier) dropping as a point load right at the end of the dividing wall, and the lateral load imposed by the tied back awning, present a logical explanation for the cracking that is evident, with larger cracks being present near the top of the wall, rather than near the floor.[11]
With respect to the cantilevered awning, the Pritchard & Francis Report explained that it was a separate, but related, matter. The report commented that the awning remained in good condition after many years, together with some calculations and assessing of its present support, led to a conclusion that it is likely to remain in a stable condition, despite the cracking in the walls. It was also noted, however, that there were 'no guarantees'.[12]
The Pritchard & Francis Report recommended chemical grouting be undertaken at 'the ends of the dividing walls under the location of the large parapet point load'. While the Respondent stated that these grouting works were never undertaken,[13] the Applicant provided itemised details of the works that did include a line item for grouting.[14] Whether the grouting work that was recommended in the Pritchard & Francis Report was ever carried out cannot be resolved by the Tribunal, but in any event, has little bearing on the current dispute.
The Pritchard & Francis Report further recommended the installation of 2 to 3 metre steel struts into the roof space to increase the stability of the awning and to assist in reducing the risk of further cracking.[15]

[61]

One might think, because the Review is pressed as a matter of public safety, that it would have been urgently progressed to enable a rapid resolution. However, that is not at all how this matter has been conducted by the parties.
As has been set out above, the Review was lodged on an urgent basis in October 2022. Unsurprisingly, an expedited hearing was initially requested, and the matter was urgently listed for final hearing in February 2023.
An expedited final hearing did not proceed due to the unavailability of relevant experts. The matter then drifted somewhat; so much so that in June 2023, the Respondent applied for the Review to be dismissed for want of prosecution due to the Applicant not diligently prosecuting its case. In July 2023, a costs order was made in favour of the Respondent.
The matter was again listed for hearing in August 2023 to enable the issues as between the parties to be clarified. The August 2023 hearing did not proceed, and that hearing was listed again for September 2023. The matter was ultimately listed for final hearing in November 2023.
However, in October 2023, the Applicant wrote to the Tribunal advising that it sought to withdraw the Review. This was because the parties had agreed to undertake the grout trial in the Building Order Review.
In its letter to the Tribunal seeking to withdraw the Review, the Applicant accepted that until the outcome of the grout trial is known, 'it cannot be determined with certainty whether or not the demolition of the building is "urgently necessary for public safety'' '.
In further support of its application to withdraw, the Application relied on its JDAP Application, which by then had been lodged, which, if approved, would authorise the demolition of the Building.
However, the Respondent did not agree to withdraw the Review for a range of reasons, including its costs thrown away and the fact that that in making the withdrawal application, the Applicant expressly reserved its right to relitigate the question again. The final hearing for November 2023 was again vacated.
In January 2024, the Applicant again applied to withdraw the Review. That application was withdrawn in April 2024.
In May 2024, the matter was listed for a final hearing in October 2024.

[94]

The small risk of partial collapse, in the context of an adverse environmental event, has now been mitigated by the presence of the temporary support structure.
Accordingly, there is no need to demolish the Building to ensure public safety.
Even if the Tribunal finds that there is an imminent risk the façade will collapse, it does not necessarily follow that demolition is urgently necessary. That is because, the parties have already agreed, by reason of the Varied Building Orders in the Building Order Review, that a grouting injection trial may proceed.
Despite agreeing to undertake a grouting trial in December 2023, the Applicant has not yet complied with the orders the subject of the Building Order Review.
The Respondent notes that, notwithstanding the detailed soil testing it has carried out; the Applicant's case is that it does not yet have 'a good understanding of soil conditions below the footpath' and therefore cannot meet the requirements of the arrangements agreed in the Building Order Review. Furthermore, the Applicant's position is that it cannot produce a scope of works due to the service providers' recommendation that the buried services in the area need to be accurately determined beforehand.
In response to these assertions, the Respondent submits that while service providers are to be notified of the works, the recommendations of these service providers should not preclude the Applicant from preparing a scope of works and eventually carrying out the required works.
Accordingly, the Respondent rejects the Applicant's explanation for not progressing with the agreed grouting trial. By failing to undertake the agreed works, the Applicant has, in effect, refused to implement what the Respondent regards as a viable alternative to demolishing the Building. Furthermore, the delay has resulted in the need for the Review to progress which would have been unnecessary had the Applicant complied with the Varied Building Order it agreed to in December 2023 in the Building Order Review.
In addition, the installation of hoarding around the Building would effectively mitigate any risk to the public.

[95]

The Applicant agrees that the phrase 'urgently necessary for ... public safety', and the elements that comprise it, are not defined nor are they terms of art. Accordingly, the phrase ought to be interpreted by reference to the ordinary and natural meaning of its terms, read and understood together.
The ordinary and natural meaning of the word 'necessary' is not limited to 'indispensable' but also includes 'vital, essential, requisite'. In its context, the phrase 'urgently necessary for public safety' does not require that the works in question be the only way that a potential risk of injury or danger to the public can be mitigated or eliminated. Likewise, the definition of 'urgent' is not limited to requiring 'immediate' action.
The phrase 'urgently necessary for public safety' must be applied in its context, rather than the separate dictionary definition or meaning of each word, divorced from that context.[55]
The Applicant agrees that item 18 provides for an exemption from the general position that works require development approval when works are 'urgently necessary for public safety'. However, it does not agree with the Respondent that the resolution of the question as to whether demolition of the Building is 'urgently necessary for public safety' turns on either of the two sub-issues identified by the Respondent (and set out at [126] above).
The Applicant emphasises that the Tribunal's task is to make the correct and preferable decision as at the time of the decision upon the Review. Accordingly, the Tribunal's findings in Sanur No 1, delivered in July 2021, are now of limited, if any, relevance.
The Applicant submits that there need not be an 'imminent risk' that the Building façade will collapse, in the sense that the collapse will occur within a very short timeframe in order to find that demolition is 'urgently necessary for public safety'.
The Applicant submits, based on the BG&E August 2023 Report, that a further rotation of 10.5 mm at the top of the parapet, or an additional settlement at the foundation of 4.2 mm, or a combination thereof, could trigger the collapse of the Building.
The temporary support structure was only designed to be in place for approximately six months and, in any event, would be ineffective as it will not prevent (or support) the collapse of the Building façade.
The Applicant submits that simply because the Building has not collapsed to date does not demonstrate that it will not do so in the future. It is not known precisely when further rotational movement and/or foundational settlement, sufficient to result in the collapse of the Building, will occur.
The Applicant does not agree that the Tribunal first needs to be satisfied that there is no other alternative to demolition of the Building that would ensure public safety, in order to find that the demolition of the Building is 'urgently necessary for public safety'. In any event, the Applicant's position is that there is no other alternative that will ensure public safety. That is so because no other option to stabilise the building foundation other than the grouting injection trial, has been proposed and furthermore, the grouting injection trial itself presents an unacceptable safety risk and is not a viable option.
The Applicant submits that the Respondent has not suggested any alternative proposal that will eliminate the risk of danger to the public from a potential building collapse. The Respondent's proposal for hoarding is not feasible, especially having regard to the adjacent footpath and Hay Street carriageway.

[97]

While the parties were not in agreement as to how item 18 ought to be read and applied, what is clear, on any view, is that for the exemption from the need to obtain development approval to be enlivened, demolition must be urgently necessary for public safety.
To determine that issue, we heard from four structural engineers, and a surveyor. Neither party sought to challenge the respective credentials, expertise or work experience of any of these experts. The one question from counsel that went to their relative experience related to their work on heritage buildings.[56] Mr Skinner, counsel for the Applicant, put to all the structural engineers that none of them had a lot of experience in dealing with heritage buildings.[57] In response, Mr Attilio Marra pointed out that he is the only structural engineer accredited, or recognised, as having heritage expertise in Western Australia.[58]
Consistent with the cases put by the parties, as well as the overall tenor in which the evidence was given, in my view, each of these experts was suitably qualified and had the requisite depth and breadth of experience. However, in saying that, the engineering evidence was sharply divided.
On one hand, the Respondent's engineers (Dr Katz and Mr Marra) are of the view that demolition of the Building was not urgently necessary. On the other hand, the Applicant's engineers (Mr MacMillan and Mr Alasdair MacKerron) consider that, in effect, the Building is not safe, cannot be made safe and needs to be urgently demolished as a matter of public safety.
While four structural engineers gave evidence, only two of these engineers had undertaken their own assessments of the structural integrity of the Building. For the Respondent, Dr Katz, who has had the longest association with the Building, has prepared various reports stemming back from around February 2021. Dr Katz designed the temporary support structure that was installed and gave evidence, which was largely accepted by the Tribunal, in Sanur No 1. Mr Marra's evidence was more in the form of a desktop review, and interpretation, of the various engineering reports that have been prepared in relation to the Building.
For the Applicant, Mr MacMillan undertook investigations into the structural integrity of the Building. His calculations were then checked internally as well as by Mr MacKerron who, like Mr Marra, undertook a review of the various engineering reports and prepared his opinion thereon.
In some respects, the engineering evidence reduces to what might unhelpfully be labelled as a 'contest' between the evidence of Dr Katz and Mr MacMillan.

[98]

Dr Katz has reported on the state of the Building on seven separate occasions following Sanur No 1.[59] Together with Mr Gaynor, he inspected the Building and viewed the tenancies from floor level. Dr Katz inspected the roof spaces of Tenancies 1, 2, 3, 6 and 7 via hatches or other openings and inspected the parapet from the roof.
In June 2022, he explained that, as was his evidence in Sanur No 1, that the structural integrity of the Building was compromised.[60]
Dr Katz outlined that the most likely cause of the lean of the façade (and associated cracking) was due to the historical settlement of the foundational material below the dividing walls. The lean extends across the entire façade but is most acute towards the centre of the Building. Therefore, the lean is not the result of localised conditions, such as patches of loose sand, but is the result of a global effect across the façade.[61] He reiterated this view in August 2022.[62] The fact that the lean is most acute towards the middle of the Building is likely to explain why there is some evidence of some movement in Pier 7 (0.043 degrees over 23 months) sometime before Horizon Surveys commenced surveying the façade .
Dr Katz notes that there are high concentrated loads below each of the piers, where the weight of the façade bears downwards. In August 2022, it was his view that the centre of gravity of the façade wall above the supporting beam remained within the 'middle third' of the supporting pad at all locations, meaning it was stable. Where the centre of gravity shifts from the middle third, rotation is more likely.[63] However, even then, Dr Katz observed that if the centre of gravity should move outside of the middle third, this does not mean that the wall would overturn. He considered that a much larger lean and eccentricity would be required before overturing would occur.[64]
At the final hearing, Dr Katz reiterated his view that the centre of gravity for the Building would need to shift a long way before the Building overturned. He explained that:[65]

[106]

Dr Katz explains that the resisting load in the steel roof frames reduces the maximum soil bearing pressures. If higher resisting forces are used, the soil pressures below the footings can be reduced further and equalised. Dr Katz concluded that the high soil bearing pressures he and the other engineers have calculated (such as to exceed 200kPa) are unlikely to have materialised, which explains that despite the high calculated bearing pressures have not translated to any measurable vertical movements in the piers and façade in recent years.[70]
Dr Katz made detailed observations of the cracks that were present during his initial inspection and has monitored this over time. He records that between 17 February 2021 and 21 August 2023 (a period of 30 months) one new crack formed (at CR05 on Wall 3) approximately 6 metres back from the façade. Two other existing cracks widened by less than 1 mm.[71]
He has also compared two photographs of the cracking recorded in the Pritchard & Francis Report (in 1989) to photographs taken in 2022. Computer analysis of the cracks suggests that over the 33-year period, they widened by only 0.6 mm and 0.9 mm.[72]
Having analysed the survey data, and consistent with the opinion expressed by Mr Bonus, which I will shortly come to, Dr Katz does not consider there has been active movement of the façade. For this reason, he does not accept the conclusion reached by ARUP that there was increased movement across the three tell-tales that were installed in February 2021. He says that this data is inconsistent with the overall presentation of the Building.
In fact, Dr Katz has long disputed the tell-tale results from the crack gauges. In his view, they were improperly installed and cannot easily, nor accurately, be monitored over time.[73] While the tell-tales suggest movement by as much as 12.5 mm since February 2021, Dr Katz was not provided with the original photographs or measurements of the tell-tales, only with the results. In his view, widening of the tell-tales in the manner described by ARUP (and BG&E) is inconsistent with the other concurrent data relating to the Building, namely the survey results which identify no recorded façade movement.
He also notes that while it may be that crack CR 10 (Wall 7) has moved by 5 mm, that too is consistent with the historic settlement of the foundation settlement discussed above. In relation to the other two telltales, Dr Katz observes that no damage was recorded on either the plaster on the other side of the wall, or, in the context of what ARUP suggests was a widening of 12.5 mm, in the plastered wall at either end of the exposed masonry where the tell-tale was installed. Furthermore, there is no cracking in the ceiling cornice above the tell-tale.
As I have explained, Dr Katz and Mr MacMillan attended a conferral in December 2022.[74] While Mr MacMillan was of the view that there was a 'risk of collapse or partial collapse', Dr Katz considered there to be 'no realistic risk' of that occurring. Both experts provided detailed reasons supporting their respective opinions.[75] Mr MacMillan pointed to the ongoing movement of the façade, as identified in the survey results since February 2021, in support of his conclusion.[76] Mr MacMillan also referred to the tell-tales installed in February 2021 as evincing movement in the Building.[77]
In his most recent report, Dr Katz concluded:[78]

[108]

Dr Katz remains of the view that the Building can be safely remediated; that the foundational material is currently stable and, moreover, can be strengthened by microfine grouting injections. He also proposes remediation works to the brick and timber superstructure such as connecting the façade to the roof structure, stitching across the cracks in the dividing walls, rebuilding small areas of masonry and providing a restraint to support the central pediment above the roof. He considers such works are feasible, straight forward and can be safely carried out.[79] His calculations confirm that the remedial works have sufficient capacity to maintain the required structural integrity.
While Dr Katz notes that these remedial works will not reverse the façade rotation that has occurred, but it will resist further façade rotation and will reinstate the structural integrity of the Building. The degree of lean is not severe from a structural perspective and is not obvious to observers.
Dr Katz is also critical of BG&E's 'risk assessment'. In his view, the risk assessment has been carried out in a simplistic fashion, producing extreme and alarmist results. He considers that BG&E's inputs into its risk matrix are a misrepresentation of the process. As an example, Dr Katz takes issue with BG&E's assessment that the hazard 'façade collapse due to vertical settlement' was rated as '4' (meaning it 'could happen anytime'). Dr Katz does not consider that assessment to be of any real utility, because the hazard factors need to be much more specific and nuanced.
That is to say, the hazard or event must be not only that the façade must collapse but it must also collapse so as to be a threat to public safety. Dr Katz's point being that a façade collapsing is rare but the façade collapsing so as to hurt someone is even rarer. That fine grained, more nuanced, analysis has been omitted by BG&E. Accordingly, in his view, the risk matrix prepared by BG&E is too blunt; and produces extremely distorted, and alarmist, results.
Dr Katz notes that there has been no recorded movement of the Building façade since February 2021, and the City's geotechnical advice was that the significant foundation movement has likely already occurred. Together with the temporary support structure, Dr Katz considers that the appropriate risk rating for a partial collapse of the façade would be 'rare'. The resulting risk to life of a collapse would thus be even rarer. Dr Katz considers that there is no realistic risk to human life, at least at this time, from the Building collapsing.[80]

[110]

Mr MacMillan is employed at BG&E. He first assessed the Building in September 2022. He has prepared three reports[82] (which he labels BG&E Report 1, BG&E Report 2 Rev A and BG&E Report 2 Rev B) and has participated in various expert conferrals.
In his first report, his observations included that there was continued settlement below the load bearing piers. He described the façade as 'active, unstable and at risk of unpredictable collapse'. He also concluded that it was not viable to remediate the Building.[83] His view was that it was unsafe to undertake any geotechnical, inground or construction works due to the unpredictable nature of the soils and that access to the Building should be restricted.[84] His report included a risk matrix, which identified that the only mitigation option that was available was to demolish the façade.[85]
He undertook a 'basic stability assessment'[86] and took account of the Pritchard & Francis Report, and the evidence of historical cracking. Mr MacMillan concluded that the remediation works recommended grout injections so as to prevent further movement of the façade. Given that the façade was, in his view, in an active state of rotation that, of itself, demonstrated that grout injections were an inadequate remediation option.[87]
To assess stability, Mr MacMillan utilised a statically determinate model[88] which assesses load paths through the structure down to the foundations. His model included an assessment of the façade stability, stability of the parapet wall, the bearing pressure on the soils together with the mass of the structure. His approach is set out further in the reasons of Sessional Member Pedersen. His ultimate conclusion was that the factor of safety (FoS) was below common industry standards.[89]
He references the three tell-tales that were installed in February 2021 and observed that while these recorded only small movements relative to the survey movements being recorded (up to 2 mm as at 26 March 2021[90] and 3 mm in July 2022),[91] he again concluded that it was evidence of the both the façade and the Building being in an active state of movement.
Mr MacMillan undertook a 'middle-third' calculation for four sections of the façade, the calculations for which included the movement being recorded by the surveys and the tell-tales. He concluded that the parapet panels at Tenancies 7, 5, 3 and 1 were deformed and are each reliant on rotational strain from the piers to remain stable and that the 'locked in' stresses cannot be relieved.[92]
Mr MacMillan then observed that movements in three of the panels exceeded those provided for in AS 1170: Structural design actions (AS 1170) which recommends allowable elastic deflections and deformity for masonry wall elements.[93] Mr MacMillan, again based on the survey results, concluded that the façade parapet was moving at particular reference points by up to 35 mm, 56 mm and 40 mm such that the recommended tolerances within AS 1170 were being exceeded.[94]
Mr MacMillan assessed the pier at Tenancies 3 and 4. He observed that the surveyed movements indicated that rotation is occurring. The unbalanced load was creating high bearing pressures at the front face of the pier foundation, which are likely to exceed 250kPa. The geotechnical advice from Galt indicates that there is no acceptable bearing pressure that can be applied to the sand foundation at shallow depth. He concluded that unpredictable (further) settlement is likely to occur.[95]
As part of the Review, Mr MacMillan attended a conferral with Dr Katz on 19 December 2022. During that conferral, Mr MacMillan set out, inter alia, detailed reasons why he considered that the Building façade could collapse imminently and was thus a risk to public safety. These reasons included:

[121]

In August 2023, Mr MacMillan undertook further site investigations and calculated revised bearing pressures. Those revised calculations indicated bearing pressures exceeding 300kPa (338kPa and 326kPa) which is considered to be 'very high for the loose sands'. In undertaking those further investigations, additional cracking was observed at the junction of the load-bearing masonry pier and the underside of the steel beams supporting the parapet wall.[98]
In August 2024, Mr MacMillan prepared a submission as part of the JDAP Application outlining the state of the Building.[99] In that submission, Mr MacMillan reiterated that long-term movement of loose sands below the Building's foundations has caused vertical rotation of the façade. He further explained that the surveys evinced 'an ongoing downward movement trend' and that 'settlement is clearly happening, trending well into the tipping point, and that is not in question'.[100]
Mr MacMillan also explained that bearing pressures on the sand exceed 300kPa (and the point at which Mr Marra considers that demolition is required). The FoS against over-turning was then assessed as low as 1.08, whereas it should be between 1.5 and 2.0. He further explained that remediation, by way of liquid grout injections, would not work given the highly stressed soils. In his view, any further settlement greater than 4 mm would cause the Building to collapse.
Mr MacMillan also took part in the structural engineers' conferral in October 2024.[101] In that conferral he explained, inter alia, that the surveys that were undertaken of the façade 'indicate ongoing vertical settlement of the façade'. Mr MacMillan reported cumulative settlements ranging from 7 mm to 13 mm. Mr MacMillan restated his overarching opinion that the façade is 'in an active state of movement'.[102]
Mr MacMillan also estimated the soil bearing pressures to be between 352kPa (for the pier with the highest lean) and 523kPa (for the pier with the smallest footing).[103] He included additional sketches and supporting information in the Joint Report, including DM002/003 which identified trending vertical settlement for three survey points between February 2022 and July 2023.[104]
In broad summary, Mr MacMillan's overall view remains that:
- (a) the Building (including the façade) has a long history of reported cracking and building settlement conditions;
- (b) the Building has moved well beyond the recommended structural limits (as defined by AS 1170);

[166]

For the following reasons, I accept the evidence of Mr Bonus that there is no evidence that the façade of the Building is, or has been since at least July 2023, in an active state of rotation.
While Mr MacMillan, as I have set out, considers the surveys evince a continuing downtrend of the façade, for the following four reasons, I disagree.
Firstly, Mr MacMillan is a qualified engineer, not a surveyor. Surveying is a discrete area of expertise. In that sense, I prefer the evidence of Mr Bonus.
Secondly, I am not satisfied that Mr MacMillan properly understood or correctly interpreted the Horizon Surveys results. I say this because he included, and insisted on relying on, survey readings which were plainly anomalous and incorrect (such as the January 2023 readings which produced artificially elevated results of up to 6 mm out), to justify this downward trend. Even after this was pointed out to him, he insisted that the erroneous data was still relevant as, in his view, it evinced a trend. That is to say, he refused to exclude survey readings that were, according to the expert in the field gathering the data (Mr Bonus), plainly incorrect and unreliable. I am far from satisfied that Mr MacMillan's approach in this regard can be accepted as sound.
Third, Mr MacMillan misinterpreted some of the survey readings (and in fact mistakenly inverted some of the results). On his interpretation the Building was in some survey readings, at the same time, moving both upwards and downwards. This only reinforces the point that Mr MacMillan's expertise is as a structural engineer, not a surveyor.
Fourth, somewhat astonishingly, Mr MacMillan explained in his oral evidence that the Applicant had been undertaking intermittent surveys of the façade.[116] However, he did not disclose such evidence to the Respondent nor the Tribunal, nor would he say what the surveys evinced, explaining instead 'we haven't used them'.[117]
In my view, Mr MacMillan's failure to reveal and produce this data is both surprising and unfortunate. This is because the Applicant in this proceeding presses its case, very loudly, that the Building needs to be urgently demolished, on the basis of 'public safety'. Viewed through that lens, one would think that it would be incumbent on the Applicant to produce all the information that informed that question of whether demolition is, in fact, necessary as a matter of public safety. How could such information not be relevant, especially if it pointed to a heightened, even imminent, risk of collapse?
It is also to be remembered here that Mr MacMillan swore an oath to tell the 'whole truth'. As was explained by the Tribunal in Harper Investments WA Pty Ltd and Presiding Member of the Metro InnerNorth Joint Development Assessment Panel:[118]

[175]

As I have set out, I am satisfied, and I find, that there is no evidence that the condition of the Building has deteriorated since 1989. As I have also found, (above at [225]), there is no evidence that the front façade is in an active state of rotation or failure.
Moreover, I also find, and it is not in contest, that the front façade has, at some point, rotated and that the bearing pressure on what Dr Katz colloquially labelled 'Subiaco sands' far exceeds levels that can be regarded as ideal. Consistent with the evidence of Dr Katz and Mr Bonus, I also find that the rotation of the façade is associated with historic settlement and is not the result of recent movement.
While there has been historical rotation and the sands are loose, the fact remains that there is no evidence of any recent deterioration in the Building's structure. That may be because, while comprised, it is stable and has been for many years. It may be because the steel struts which were inserted into the roof in 1989 (all but one of which remain) are holding the structure together or it may instead be that the temporary support structure has been engaged, as put forward by Mr MacMillan and Mr MacKerron. It is not possible to tell in any absolute sense. However, the last explanation, that the temporary support structure is now engaged, seems unlikely, based on the Tribunal's findings in Sanur No 1, which predated its installation. Furthermore, the temporary support structure was not designed to, and would not, prevent the collapse of the Building.
While the Applicant's case is that things have moved on from Sanur No 1, as I have set out, it was agreed that there is no positive evidence that the Building has deteriorated further. That is so, even though far more is now known about the Building, including the stressed nature of the sands and the precise location and dimension of the piers. However, the more that is known about the underlying sands and the pier structures does not, of itself, lead to a conclusion that the demolition of the Building is now urgently necessary as a matter of public safety.
Whatever the Applicant says about the apparent urgent need to demolish, I come back to the fact that there is no evidence, from the public safety standpoint, of any recent change to the Building's condition or its risk profile. That is to say, there is no evidence that the Building is any worse state than it was in 1989.
In fact, from a public safety viewpoint, the situation is much better because the Building is now being actively monitored by the City via monthly surveys. Those surveys indicate, as I have found, that the Building is not in an active state of movement.
The fact that the geotechnical reports indicate that the sand underneath the structure is loose towards the surface (to a depth of varying degrees, up to 1.65 metres) does not change the fact that the Building currently presents as stable and there is no definitive evidence of any change since 1989, and more particularly since Sanur No 1 was delivered in 2021.

[182]

Thirdly, Dr Katz has had the longest association with the Building (including designing the temporary support structure) and was able to offer an insight into whether there has been any discernible changes to the condition of the Building since Sanur No 1. Of course, that cannot be the end of the analysis, and I accept the length of time he has been monitoring and consulting on the Building does not, of itself, mean that Dr Katz is correct.
But in circumstances where questions of public safety are involved, in the context of an argument that a building has deteriorated so as to be, in effect, at, or even past, the point of collapse, the length of time an expert has been observing that building is not, in my view, an irrelevant consideration to take account of when assessing their respective opinions.
Moreover, Dr Katz is not an employee of the City. He has been engaged as an independent expert to advise the City and, on review, the Tribunal at discrete intervals since 2021. In his view, the Building presents today in the same condition it was in at the time of Sanur No 1. As I state above, Dr Katz gave frank and fearless opinions in a manner suggestive that he was not invested in any particular outcome.
Fourthly, while he has had the longest association with the Building, it is not the case that Dr Katz is a witness that has long ago reached a view about the Building that he will not be moved from. He did not approach his evidence with a closed mind. To the contrary, the Applicant is highly critical of Dr Katz for revising his opinions as new information has come to hand. As I will come to explain, I do not accept that criticism.
In the end, the explanation offered by Dr Katz, which I have set out above, aligns with my view of how the Building currently presents, and is consistent with what is, as I have stated, the engineers collective view that while there has been some historical rotation of the façade, the Building has been stable since at least 2021. While the structure may be compromised, there is not an imminent risk of collapse. I agree with Dr Katz that the tell-tale evidence pointing to significant movement within the Building is anomalous and does not at all align with the survey results which show that the façade has not moved. In this regard, I note the Tribunal in Sanur No 1 reached the same conclusion about the apparent disconnect between the tell-tale readings and the stability of the façade.[130]
In finding that the Building is not at an imminent risk of collapse, while I am not in any way bound by Sanur No 1 and must approach the Review afresh, I am cognisant that my view broadly aligns with the Tribunal's findings in Sanur No 1 where Dr Katz's evidence on the state, and structural integrity, of the Building was largely accepted.
Based on Dr Katz's opinion, in Sanur No 1 the Tribunal concluded that 'the façade wall is not in an active state of movement or rotation, despite evidence of widening cracks in party walls, and is not in imminent danger of collapse'.[131]
In 2025, I have, in effect, reached the same conclusion based on the updated evidence presented in the Review. Moreover, my conclusion is further bolstered by the more recent survey results which, in the opinion of Mr Bonus which I accept, confirm that the façade is in an active state of rotation. Yet I am mindful, as the Tribunal was in Sanur No 1,[132] that the façade does pose a safety hazard and does warrant action being taken without further delay.
While I accept that the Building may ultimately collapse without any prior warning, I do not consider such an outcome to be reasonably likely, at least in the short-term. Dr Katz's overall opinion was that the Building 'has some way to go' before its demolition could be regarded as being 'necessary as a matter of public safety'. Accordingly, while I do acknowledge there is a risk of an uncontrolled collapse, I do not consider such an eventuality to be reasonably likely at this time so as to justify the urgent demolition of the Building as a matter of public safety.
It is also necessary to address Mr Skinner's criticisms of Dr Katz whose evidence he labelled as, in effect, a 'moving feast'. In my view that submission is unfair. Dr Katz's evidence was preferred by the Tribunal in Sanur No 1 and since that time, as the Applicant is at pains to point out, more information has come to light including information about the nature of the soils, the bearing pressure as well as the physical dimensions of the piers.
As more information has come to light, Dr Katz has adjusted some of his assumptions, including during the conferral of the structural engineers. I do not accept that Dr Katz should be criticised for this. While it is true that some of his modelling, such as the finite element modelling, which has informed his opinion and which he did speak to in his viva voce evidence, was not put before the Tribunal,[133] the Applicant could have, but did not, call for this modelling to be produced. More than that, given the long history of this matter, it is not a situation where there is a scarcity of materials before the Tribunal. Indeed, the opposite is the case.
I also reject the criticisms made of Dr Katz that his calculations were not checked by other engineers. Dr Katz, quite reasonably in my view, assumed he was giving expert evidence on an independent basis and, in doing so, his work had to be his own. While I do not criticise Mr MacMillan for having his calculations checked by another engineer, I do not consider Dr Katz should be either for attempting to, as he understood it, stay faithful to his obligations as an independent and impartial expert witness.
As I have set out above, the simple fact is that the Building presents many unknowns, particularly from the perspective of the Applicant's experts. That is because, if they are to be taken to be correct, the Building should have collapsed long before now. But it has not and there is not a jot of recent evidence that it will do so in the short-term. As I have already explained, whatever else may be said about Dr Katz, in my view, his opinion best reflects how the Building currently presents. That is, as an old building of some heritage significance which is compromised and in need of repair, but which is presently stable and has been for a long period of time.
This matter is made more complex by the age of the Building and the fact that no structural engineer knows, categorically, how it was constructed and why the structure presents as it currently does. What can be said is that whatever construction method was used, it sits well outside of contemporary building and design standards.
While I prefer and accept the evidence of Dr Katz, it is necessary to explain my impressions of the evidence of Mr MacMillan and, to a lesser extent, Mr MacKerron.

[186]

BECKETT, MR: So we were told it's moving. We discussed the Peter Bonus evidence. There was cross-examination about the graphs and the outliers. There were then some concessions on day 2 that maybe the results don't show what it said - sorry, what they said it initially showed, and then we had a strange - again, repeated this yesterday. So we've got Mr MacMillan saying that the building is in an active state in his reports.

He also states it specifically at item 5 of the joint report, so the most recent relevant thing he has filed was still up until that point relying on an assumption that the building is active. When confronted with the evidence that it might not be active, he said it didn't matter. It's not relevant. Mr MacKerron didn't quite go that far, but he made a similar remark - it doesn't matter whether it's moving or not.

It was remarkable to hear that, after so much of their evidence and their conclusions was entirely predicated as that being a key factor behind the instability of the building. It doesn't matter. It's not relevant, but we will produce cherrypicked graphs to show what we want it to show, that apparently do show movement. But then when we're confronted on that we say that we didn't actually rely on those at all. And it's just a fact, and it's just part of what was put to the Tribunal.

But that didn't stop there. ...- they say they didn't rely on it at all. Yesterday under cross-examination, or reexamination, I should say, Mr MacMillan said he didn't even use that information in any of his conclusions. And then again, confronted with his own report, his own calculations that clearly shows the 2024 surveys factor in movement - and this is evidence he has given for four days as to his conclusions about the safety of the building, and then at the end of the final hearing he says yes, okay, I did have regard to those assumptions.

He initially denied it. Ultimately said that that is part of what he took into account. It's in the preamble to the risk assessment he prepared. It's referenced in the 2022 BG&E report. It's littered throughout their evidence. And then strangely, when confronted with the possibility that maybe the building is not moving, they're response is that it doesn't matter anyway, and it's not relevant. We don't understand it.

[187]

I share Mr Beckett's concerns with this aspect of Mr MacMillan's evidence. I do not accept Mr MacMillan's explanation that the lack of movement in the façade was not really relevant to his assessment as to whether the Building needed to be demolished. His response to what was a significant issue as between the parties is inconsistent with his many prior written reports which placed considerable, indeed significant, weight on the surveys evincing a continued downward trend in his overall assessment of whether demolition of the Building was urgently necessary. His refusal to adjust his views, to any degree, once he was made aware he had misinterpreted the survey data leaves me with the impression that he is a witness invested in a particular outcome.
I have set out above (at [259]) that one of the reasons I accept the evidence of Dr Katz is because his opinion best describes how I consider the Building currently presents.
On the other hand, Mr MacMillan commenced the hearing with very strong views that the façade was moving based on the survey evidence. He also placed significant weight on the fact of the loose sands and his calculated bearing pressure which, in his view, pointed to an imminent failure of the Building. Like the Applicant's engineers in Sanur No 1, the movement identified in the tell-tales was also relied upon.
In my view, Mr MacMillan's opinion does not align with the condition in which the Building currently presents. Mr MacMillan calculates that the bearing pressure on the sands has exceeded the point at the façade where it may be expected to collapse, in circumstances where there is no evidence of any deterioration of the Building since 2021. He also regards as important the tell-tales, which indicate to him significant internal movement within the structure, but which has not translated into any movement of the façade during this time. The state of the Building as described by Mr MacMillan does not align with what I have observed and understand to be the case. For these reasons, in my view it is open to conclude, without intending any criticism, that Mr MacMillan is simply incorrect in his assessment of the Building.
While I do not accept his evidence, I must also say that I do not regard Mr MacMillan as an impressive witness. I find he did not present his evidence in a neutral nor impartial manner. His evidence, both written and viva voce, appeared to me to be excessively pedantic and directed to delivering the outcome his client has long been seeking, rather than offering his expert opinions so as to assist the Tribunal. My reasons for reaching this view are as follows.
Firstly, as I have set out, I am concerned that he has not been completely forthright with the Tribunal. He was aware of surveys of the façade that were commissioned by the Applicant but did not refer to this data in his witness statement or otherwise provided it to the Tribunal. In a case where the Applicant is raising the question of public safety, and where it was asserting that survey evidence indicated the façade was moving, to completely omit, or even refer to, such data is, in my view and putting it gently, most unfortunate.
Secondly, Mr MacMillan 'cherrypicked' the Respondent's structural engineering evidence in a manner which significantly distorted the opinion being expressed. For example, in his report Mr Marra explained that:[138]

[191]

Mr Beckett put to Mr MacMillan that he omitted 'a pretty fundamental' aspect of Mr Marra's opinion. Mr MacMillan replied that he was seeking to highlight and discuss the threshold bearing point of 290kPa to 300kPa. While Mr MacMillan explained that he was not intending to misrepresent Mr Marra's opinion, he did take licence with it in a manner which did, in fact, distort it, such that it appeared to create a narrative that aligned with his opinion that the threshold load bearing capacity had already been reached such that the Building could not be repaired.
Mr Marra's actual opinion was that further rotation of the Building would be necessary in order to reach the requisite stress level on the sand. I agree with Mr Beckett that it was quite a fundamental omission. Furthermore, the above example was not the only one of this kind.[140] Moreover, this kind of misrepresentation of Mr Marra's opinion is consistent with my broader concerns that Mr MacMillan took it upon himself to advocate for Sanur's position at every opportunity.
Thirdly, as an example of his pedantic approach, when he was questioned as to what public safety risk would remain if the pedestrian footpath along Hay Street were closed, together with the adjoining car parking bays and even a portion of Hay Street (so as to exclude the public from any area where the Building may collapse), Mr MacMillan's concern then turned to the potential impact on public safety arising from the dust cloud that may result from any collapse.
His evidence here further highlights my concern that he was not impartial. It is, quite frankly, nonsense to suggest that there is a public safety risk from a dust cloud that would no doubt form (and then dissipate) if the Building collapsed. As I have explained, the impression I have of Mr MacMillan is that he is a witness desperate to find any and all reasons to demolish the Building.
Finally, while Mr MacMillan is, of course, entitled to take a conservative view, especially in the context of a question of public safety, it is not irrelevant that his very conservative views and assumptions all went in Sanur's favour that the Building is, in effect, too unstable and must immediately be demolished.
An example of this conservatism is that he had no regard to the stability that might be provided by the supporting street struts that were inserted after the damage to the building in 1989 because he observed some damage to one of them. However, Dr Katz disputes that all the steel struts are damaged[141] as there was more than one street strut installed in the roof. The point being that Mr MacMillan's conclusion that the Building is at the point of collapse is premised on a series of (in my view, overly) conservative, and at times pedantic, assumptions which have been relied upon to inform his FoS (which is now less than one on his calculation).
In fact, based on Mr MacMillan's interpretation of the survey results from 2024, he suggests that the temporary frame has already been engaged. That observation itself is somewhat curious given the temporary structure is not designed to withstand the failure of the façade.
For largely the same reasons as Mr MacMillan, Mr MacKerron considers that the Building is at the point of collapse. Accordingly, in rejecting Mr MacMillan's evidence, I also do not accept the evidence of Mr MacKerron who, in effect, reviewed, checked and agreed with the conclusions of Mr MacMillan.
For these reasons, I prefer the evidence of Dr Katz over the evidence put forward by the Applicant's structural engineers.

[193]

In terms of how Pt 7 of the deemed provisions operates, the opening provision is cl 60 which provides that a person must not commence or carry out, relevantly, 'works' on land unless development approval has been obtained or because the development is exempt from the need to obtain development approval under cl 61. The definition of 'works', includes 'demolition'.[142] Therefore, unless the development in question falls within an exemption provided by cl 61, development approval is required for all 'development'.
The statutory scheme evinces an intention that demolition works on heritage-protected places are, in the ordinary course, to be authorised by way of a development approval prior to applying for a demolition permit under the Building Act. The effect of item 18 in the Table in cl 61(1) is to exempt 'demolition works' on some heritage-protected places (including the Building) where such works are, relevantly, 'urgently necessary' for 'public safety'.
In my view, the composite phrase 'urgently necessary for public safety', in this context, does not invite a broad interpretation. Rather, it is to be interpreted according to the ordinary and common meaning of its terms understood together and read in context. It is also the case that planning schemes are to be construed sensibly and practically,[143] in a manner consistent with their town planning purpose.[144]
Accordingly, the exemption in item 18 applies to demolition works where a permit-authority, and on review the Tribunal, are satisfied that such works are urgently necessary as a matter of public safety. That is, the demolition works must not only be 'necessary' but must also be 'urgently' necessary in order to protect or safeguard 'public safety'. The use of the word 'urgent' in this context plainly imports a temporal aspect.
Reading and applying LPS 5 sensibly, practically and consistent with its legislative purpose, the exemption in item 18 applies where the circumstances are such that, in order to secure public safety, the heritage protected place must urgently be demolished and, because of that, there is insufficient time for the development approval process, that would ordinarily apply, to be followed.
As I also raised in oral argument, to my mind item 18 is drafted as a provision that, in effect, operates to authorise or excuse the demolition of heritage-protected places that are required to be, or may have already been, pulled down in urgent circumstances.
I struggle to see it as a provision that the drafters intended, as is the case here, to form the basis of a Review which has now been before the Tribunal for almost three years, in circumstances where the parties have delayed the final hearing for almost two years, where the Applicant has sought to withdraw the matter more than once and where the expert engineers have agreed that there is no evidence of any further deterioration of the Building since Sanur No 1 was delivered in 2021.

[195]

For the reasons I have already set out, I am not satisfied that demolition is 'necessary'. That is to say, I am satisfied, and accordingly I find, that demolition of the Building is not 'vital' or 'essential' as at the date of the decision on the Review.
While, for reasons I come to shortly, the reviewable decision before us does not extend to making any binding determination as to whether the Building can be remediated or saved, this case did canvas microfine grouting injections as one possible option. Indeed, the evidence of Mr Derek Craig, a grouting contractor, went to how a grouting trial might proceed.[145]
It is also the case that parties agreed orders for a grouting injection trial in the Varied Building Orders which is yet to be actioned. As was also canvassed in oral argument, there are other possible remedial actions that may be contemplated, and which were not the subject of any detailed evidence.[146]
While I accept Mr MacMillan did consider whether some remedial actions would be 'viable', I do not accept his evidence in this regard. I am not satisfied that this evidence represents a robust and exhaustive consideration of what remedial options may be available. The simple fact is that Sanur wants to demolish the Building. As I have explained, in my view, Mr MacMillan tailored his evidence to very much align with Sanur's long-held intentions.
Moreover, as a structural engineer, I am far from satisfied that Mr MacMillan is qualified to draw any definitive conclusion as to whether a particular remedial option is financially 'viable'.[147] His viability assessment in this regard includes no costings nor financial analysis. In addition, there was no evidence in this proceeding as to the Building's heritage significance and any contribution it may make to the public realm as a 'heritage-protected place'.
The heritage significance of the Building, in its context, may well be a factor that informs any conclusion as to whether remediation is 'viable'. The point being, in the context of heritage places, economic factors may not be the only considerations that inform whether a remedial action might be 'viable' or not.
For this reason, I am not at all satisfied that the Tribunal has all the information that would reasonably be required to determine whether any remedial actions to restore the Building would be 'viable'.
Because I have found that the demolition of the Building is not, at this time, necessary, it follows that I am also not satisfied, and I find, that demolition of the Building is 'urgent' for the purposes of item 18.
Accordingly, I am satisfied, and I find, that demolition of the Building is not 'urgently necessary' as a matter of public safety at this time.

[197]

It is also necessary for me to explain why I reject the Applicant's submission to the effect that once it has shown that the demolition of the Building will address any public safety issue, the burden or onus then shifts to the Respondent to demonstrate, on the balance of probabilities, that the Building can be saved via some means such as grouting injection trials or some other option. Three things can be said about that.
Firstly, in my view, it is a lazy argument. It is of course the case that the demolition of a structure is an outcome that will always secure public safety. If Mr Skinner were correct, in all instances, once a landowner says they wish to urgently demolish a building as a matter of public safety, the burden in these types of disputes swings onto a respondent permit-authority to incur costs and investigate remediation options other than demolition. That simply cannot be the intent of the legislative framework.
Secondly, in my view, s 119 of the Building Act does not support that argument. Section 119 provides a right of review of a decision to refuse a demolition permit. That decision is the reviewable decision for the purposes of the Tribunal.
The Tribunal is a creature of statute. We are only entitled to exercise the jurisdiction that arises from the reviewable decision. We have no incidental or supplementary power beyond those functions and discretions exercisable by the Respondent in making the decision under review.[148]
In this instance, the Review arises by reason of the Respondent's refusal of the Application on the basis that it was incomplete by reason that approval for the development 'works' had not been obtained under LPS 5, for the purposes of s 21(1)(j) of the Building Act. That decision is the reviewable decision.
Accordingly, our task begins, and ends, with a determination of whether the circumstances are such that it is unnecessary for the ordinary statutory path of obtaining a development approval for demolition works to be followed because it is 'urgently necessary' as a matter of 'public safety' to demolish the Building.
Thirdly, and following on from above, as the High Court has observed, as an administrative tribunal, we have a 'duty and concomitant authority' to ensure that we act, and remain, within our jurisdiction.[149] Likewise, on more than one occasion that Court of Appeal has reiterated that, in its review jurisdiction, the Tribunal must remain within the metes and bounds of the reviewable decision.[150]
In this case, the simple fact is that the Respondent made no reviewable decision as to whether the Building was, in fact, capable of being saved, remediated or otherwise. The decision that was made, and that is the subject of the Review, was that the Application was incomplete. Accordingly, we have no authority in the context of an application for a demolition licence, to step beyond the reviewable decision and start offering what would be, in effect, no more than an advisory opinion on a question which is simply not before us.
I therefore decline Mr Skinner's invitation to tempt the Tribunal down a path and reach a finding as to whether it is even possible to remediate the Building, as that question is outside of the reviewable decision before us and, in any event, as I have explained, we do not have sufficient information to fully address that question.

[199]

It is important that I emphasise that my findings above are limited to the discrete question of whether the demolition of the Building is urgently necessary as a matter of public safety, such that the Application made in September 2022 was, in fact, compliant with the requirements of s 21(1)(j) of the Building Act.
While the effect of this decision is that approval for the demolition works is required under LPS 5 before a demolition permit can be issued, I offer no opinion as to whether development approval for such works ought to be given.
That is an argument for another day and that decision may well have to grapple with the question as to whether the Building is such that its remediation and repair is not viable. As I have explained, that question itself may well involve consideration and a balancing of the financial cost of such works as against the heritage value of the Building. It may well be that the heritage value of the Building does not justify what might be an expensive restoration exercise. However, that is not a question we have had to consider in the Review.
By reason of the refusal of the Demolition DA in 2021, the Applicant had the opportunity to present to the Tribunal its case as to why development approval ought to be granted for the demolition of the Building. That argument would have no doubt included the arguments presented in this case, including the compromised state of the Building but, in addition, could carefully consider the viability of remediation options in the context of its assessed heritage value. However, in contrast to the many reviews it has lodged in the Tribunal, the Applicant chose not to challenge the City's decision. It instead progressed the Review on a standalone basis.
In reaching this decision, I implore the parties to now engage constructively on the question of the fate of the Building. It is clear to me that this saga has pushed the parties into respective corners such that meaningful engagement on the state of the Building, and the way forward, appears to have ceased long ago. The process of dealing with the Building now seems to being run by law firms, not engineers. In this context, that is hardly ideal.
While I find that the demolition of the Building is not, as at the date of the decision on the Review, urgently necessary, that does not mean it does not present any risk to the public. It plainly does.
The City and the Applicant need to urgently, and meaningfully, engage on the future of the Building. This saga has already dragged on for way too long.

[204]

Willey SM has provided a summary of the some of the evidence included in Mr MacMillan's witness statement. I emphasise the following additional points.
Mr MacMillan holds a First-Class Honours degree in Civil & Structural Engineering, is a member of The Institution of Structural Engineers and a Chartered Engineer. He has well over 30 years continuous structural engineering experience since 1986.[151] He has been employed by BG&E in senior technical roles since 2003, with vast experience in the structural design and modification of a large and diverse range of structures and foundations. including, relevantly, landmark heritage buildings.
Mr MacMillan performed stability calculations on the parapet wall sections and piers using a statically determinate model which tracks the load path through the main building elements down to the foundations. The model looked at façade stability, parapet wall stability and foundation soil loading (bearing pressure) under gravity loads (mass of the structure). He compared stability with the industry-accepted value of 1.5 to 2.0 for working loads.[152] He reviewed bearing pressures under the footings with respect to the advice of the geotechnical consultant.
The calculation first looked at the Building in its original as-built configuration to provide a baseline of the safety and stability of the Building when it was constructed. Under these conditions the loads from the parapet wall onto the supporting steel beams act within the middle third of the wall, thereby placing the bricks in full contact with the supporting steel beam and maintaining the brickwork in compression across the whole section. Loads from the pier footings onto the footings also act within the middle third of the pier, likewise, keeping it fully in compression. The as-built peak bearing pressure under the pier footings was calculated at between 145kPa and 245kPa, with contact pressure onto the underlying soil acting across the whole of the footing and the calculated FoS for overturning on the as-built pier being 1.3 to 1.7.[153]
Once the rotations of the structure were taken into account, the resulting deflections of the parapet wall were assessed against the requirements of the AS 1170 recommendations for deflections of masonry elements. The along-span deflections in a number of panels and the height-span deflection in all panels exceed these recommendations.[154]
The parapet wall was assessed in a number of locations to determine whether, after the movement of the façade, the weight of the wall was still acting within the middle third of its section. It was found that '[d]ue to recorded movement, large sections of the existing façade parapet have a centre-of-mass outside the section's middle third, resulting in tensile stress being induced in the parapet wall'.[155] Mr MacMillan noted that such tension forces should be avoided in masonry elements due to the low tensile capacity of masonry.
The piers were assessed for stability. Mr MacMillan included a section of the dividing wall behind the pier as a stabilising element. The stability factors in the piers were found to be between 1.0 and 1.1 for the 2021 surveyed movements. In the steel column location, the stability factor was 0.98.[156] Mr MacMillan noted that industry standard is for these factors to be in the order of 1.5 to 2.0, meaning the piers are significantly less stable than is required under Australian Standards. At a value of 1.0 the destabilising loads equal the stabilising loads, so the calculations show the piers are very close to failure under gravity alone.
Peak bearing pressures calculated under the pier footings were as high as 393kPa when calculated for the façade lean as indicated in the 2021 survey results. Mr MacMillan also noted that further foundation settlement was likely to be induced by the high bearing pressures, leading to a self-perpetuating cycle of load increase and additional settlement.[157]
To 'provide relevance and context to the middle third checks', Mr MacMillan calculated the additional building movement required to reach the point when the resultant load of the pier moves outside the front edge of the footing, leading to uncontrolled collapse through overturning. The calculated additional settlement is 4.2 millimetres under the footing, or an additional 10.5 millimetres additional lateral movement of the top of the parapet wall.[158]
Mr MacMillan noted that the calculations above have taken only gravity loads (the weight of the structure) into account. The inclusion of environmental loads such as wind and earthquake loading into the calculations would further reduce the FoS.[159]
Mr MacMillan noted that secondary elements are most likely acting to resist the overturning of the parapet wall and piers. The contribution of the steel ties across the dividing walls is difficult to quantify, there is evidence of bolt failure in the bolts through the wall holding the ties in place. Likewise, the roof timbers are in poor condition and their capacity is indeterminate. The deformation of the parapet wall indicates it is taking lateral loading as locked-in tensile force across the front face of the brickwork. Mr MacMillan stated that it is inappropriately unconservative for these secondary elements to be relied on and that to comply with industry standards the loads should be transferred to the foundations by the main structural elements of the façade.
Mr MacMillan pointed out during the site visit that the bearing pads on the temporary frame towards each end of the building were no longer in contact with the parapet wall, and that there is tension in the straps to the concrete block weights. This was supported by observations made during the site visit. Mr MacMillan's interpretation of this was that it is likely there has been a partial load transfer to the temporary frame.[160]
Mr MacMillan has modelled the temporary support frame and finds it is sufficiently stiff to absorb some lateral load from the Building façade and prevent additional outward movement at the centre of the parapet wall.[161] Mr MacMillan suggests therefore that secondary elements including the support frame, roof structure and out-of-plane bending of the parapet wall are actively resisting the outward movement of the parapet and overturning of the façade. This has identified a concern that removing the temporary support frame or failure of any of these elements may now lead to a sudden outward movement of the wall and subsequent brittle collapse.
Mr MacMillan advised that his calculations were checked by Ms Tania Crawley BEng, Technical Director at BG&E with 18 years' experience in structures. They were then provided to Mr MacKerron for independent review.
Mr MacMillan carried out trend analysis of the survey data and found this indicated a potential movement downward of the façade, noting that each survey point is subject to tolerance-based variation, and it is a weak trend. He acknowledged he had inverted the movement on one survey point, leading to an inversed trend (indicating an upward movement of the pier rather than the downward trend identified by Mr MacMillan).
Mr MacMillan's interpretation of the Galt Geotechnical Report is that the soils under the foundation cannot be safely or practically remediated. He noted the geotechnical consultant's advice that there was no safe bearing pressure that could be advised for the loose sandy soil foundation.
In the final hearing, Mr MacMillan outlined his professional experience with injection grouting projects, both to support soil behind excavations and to provide remedial supports to the strip footings of walls where foundations were inadequate. He noted that he had observed cases where the grout had not penetrated under footings, which only became apparent when the area was excavated, and he stated this occurs in around 60% of cases. He has observed excavations that collapsed because the grout had not engaged. The applications where he would recommend grouting is for strip footings that are grouted in sections, so the wall bridges across the grouted area while the grout engages, or to stabilise shallow excavations. He noted that grouting is not a good solution where it is required to permeate under pad footings, particularly where highly loaded like the pier footings of the Building and he has never specified grouting in this scenario for this reason.
Mr MacMillan advised that grouting under these pier footings on the Building, with a high stress on a small area, could cause building collapse in this case because the injection of liquid into the soil under the footings could lead to consolidation of the soil, loss of bearing capacity and foundation settlement. In addition, Mr MacMillan advised he could not certify that the grout block installation would achieve the required bearing capacity because of the inability to confirm the grout had satisfactorily permeated under the footing.
Having determined the current state of the Building, Mr MacMillan's September 2022 report went on to carry out an assessment of the viability of a number of stabilisation steps and methodologies.[162] This provides a detailed analyses of whether the design/outcome can viably be designed and certified for each method at each step, whether safety/risk can be viably addressed and whether it is financially viable. His conclusion was that there was no series of remediation steps that could be considered viable, and indeed none of the methods met all three viability criteria.
Mr MacMillan reviewed the items listed in the current Building Order. Mr MacMillan's assessment was that most of the items in the Building Order were either unsafe, ineffective or both.[163] He further noted that injection of grout would not only potentially destabilise the soil under the footings but was also likely to cause ingress to the disturbed soil in the services corridor, potentially into service pits and encasing conduits and pipes.[164]
In compliance with the safety and design requirements of the Work Health and Safety Act 2020 (WA) to fully inform clients about risk levels, potential mitigating actions and residual risk, Mr MacMillan included a comprehensive risk assessment in his September 2022 report. He provided evidence that the risk assessment accords with industry standards. The only action that mitigates the extreme risk identified is safe demolition of the façade.[165]
Mr MacMillan's evidence about the temporary frame was that it is likely providing partial restraint that controls the outward movement of the parapet, despite this not being the design intent.[166] He noted that the frame will not prevent settlement of the footing or rotation of the piers and is therefore not providing vertical restraint to the structure.
Mr MacMillan worked with Galt to undertake additional soil testing in May/June 2023. The footings are shallow, sitting at 0.4 metre deep with a thickness of 250 - 300 millimetres by around 1 metre wide. The soil was tested adjacent to the footing. The Perth Sand Penetrometer results reported by Galt[167] start at the base of the footing. The soil is variably characterised as 'very loose' to 'dense' with the general description being 'natural sand' that is 'loose to varying depths (frequently 0.7 to 1.0 metre) before becoming medium dense to dense below that depth'. Mr MacMillan sought advice from Galt on the high, non-uniform bearing pressures calculated under the pier footings and Galt advised that they '... are at or beyond levels that we would consider the ultimate bearing capacity of a loose sand foundation. This also leads to unpredictable foundation responses and settlement'.[168]
Mr MacMillan noted that there is no redundancy in the structure and that failure of the Building would be characterised as a brittle failure, being potentially without warning, sudden and catastrophic. In addition, it is a progressive, or self-perpetuating failure because any settlement due to high bearing pressures will rotate the structure, which increases the eccentricity of the load due to building lean, which further increases the non-uniformity and peak magnitude of the bearing pressure under the footing.
Mr MacMillan advised that the footpath and parking should immediately be closed and advised that rubble and dust may still pose a risk even if pedestrians were diverted to the other side of the road. He referenced the clearance envelope calculated by Structerre under AS2601, which stipulates an exclusion zone for controlled demolition of 1.5 times the building height.

[205]

I concur with Willey SM that in the main, evidence by Mr MacKerron mirrors and supports the evidence provided by Mr MacMillan. I emphasise the following additional points below.
Mr MacKerron has over 30 years' experience in a career that was founded on significant civil and structural engineering design experience with additional experience in geotechnical advice and project delivery.[169] His current role has key responsibility for project delivery and risk management including a variety of building projects. His experience is focussed more broadly than purely structural engineering but encompasses a significant exposure to and overall responsibility for the structural aspects of a wide range of projects including in heritage buildings.
Mr MacKerron noted that staging the grouting works could introduce differential settlement and a redistribution of the loads and locked-in stresses in the structure which may in itself precipitate collapse.
Mr MacKerron identified that the glazing has leadlight sections above the plate glass in each tenancy, and these have deformed, and this was observed during the site view. Mr MacKerron's view is that this shows some downward movement of the parapet wall beams has occurred.
Mr MacKerron confirmed he had checked and reviewed Mr MacMillan's calculations and accepted them as correct. He is also of the opinion that the temporary frame is currently taking load and that if removed, there may be residual stresses that release. He concurs that the timing of failure is not predictable, that the failure may be sudden and catastrophic (brittle failure) and that there is no way to determine the actual buffer against failure.
Mr MacKerron confirmed Mr MacMillan's risk assessment process as being in line with industry standard with a sufficient degree of granularity to help prioritise risk.
Mr MacKerron identified that catastrophic brittle collapse may occur in structures where there has been little or no prior warning, and the continuing lack of collapse in a structure does not render it safe, indeed this promotes a dangerous sense of complacency. The example he provides in his report is the Westralia Square pedestrian bridge where reinforcing was not adequately anchored yet the bridge remained in place until its sudden and catastrophic collapse.
Mr MacKerron's assessment of the Building is that failure could occur at any time, and that the configuration and likelihood of locked-in stresses in brittle elements of the Building indicate that failure is likely to result in sudden collapse.
Mr MacKerron addressed the question of whether Australian Standards should be strictly applied to heritage buildings, given the Building has stood for a long period. He noted that it may be reasonable in some circumstances to accept that a heritage building does not meet current codes, but the full picture needs to be considered to understand any changes that have occurred over the building's life. In this case the Building is not in its original condition, is cracked, there are known poor ground conditions and it has rotated up to 165 millimetres at the top. Simple statics is demonstrating that it is not sufficiently stable. In this case Mr MacKerron indicated that there cannot be reliance on unknown material strengths as the failure mechanism is not reliant on material strength, instead simple statics are demonstrating the Building is at the point of overturning under gravity loads alone.

[206]

Willey SM has provided a summary of the some of the evidence included in Dr Katz's witness statement. Additional elements of Dr Katz's evidence are included below.
Dr Katz graduated in 1988 with honours in engineering while under apprenticeship at British Aerospace. He then specialised to post-doctoral level in biomedical engineering. He moved into structural engineering in 2011 after a gap of 20+ years since completing his degree. He spent the next four years undertaking design and site roles for mining and infrastructure works. From 2015, Dr Katz has worked in a residential and commercial project environment, including, relevantly, a range of heritage buildings works. In 2022 he formed his own company to continue his consultancy work.[170]
In the hearing, Dr Katz addressed the identification of a loose sand profile in the zone below the footings, noting that given the age of the Building he would have expected greater compaction. His explanation of the loose soil conditions was that possibly the bearing pressure is lower than has been calculated or the sand is denser under the footings. He also expressed the view that because movement was not occurring, that the Building was stable in the short-term.
Dr Katz noted that, without remediation, it is likely that further settlement and rotation of the foundations would occur in the long-term. He based this on his evaluation of geotechnical advice, noting Galt's advice that external influences such as water ingress and vibration could lead to settlement due to the meta-stable nature of the soil - being currently stable but subject to potential consolidation due to external factors and longer-term settlement. From this he inferred that settlement was not likely in the short-term and there is a 'window of opportunity to remediate the façade in the short term'.[171]
Dr Katz also noted that Local Geotechnics considered further movement was unlikely due to 'reasonably expected current and transient loading conditions, and with due consideration of existing structural restraint of the piers'.[172]
Dr Katz identified that remediation of the foundations is required. He refers in the joint statement to the advice of 'geotechnical engineers and grouting specialists that microfine grout injection will be the most appropriate method for strengthening the foundation material'.[173] Grout injection is included in the list of strengthening requirements under the Respondent's building order, and this list originated in the letter from Keystone Structural to the City, dated 9 August 2022.[174]
In oral evidence, Dr Katz identified that it is not his role to determine whether grouting is suitable, however he also said that grouting is a solution if it can be installed. When asked whether the risks can be mitigated, his response was to try and see, and if there was excess permeation (e.g. into the service corridor) the trial could be stopped. He then suggested grout trials away from the footing as the initial test scenario could also be used to mitigate risk.
On 17 March 2021, the Respondent issued a Building Order to the Applicant to install the 'temporary support structure' designed by Dr Katz.[175] The intent of the temporary support structure is identified in City of Subiaco Council minutes of 3 March 2021, being to '[protect] people and property from a potential uncontrolled collapse'. In these minutes it was identified that the City was working with Quoin to 'engineer an appropriately rated design' for a frame to 'act as a barrier in the unlikely event of an uncontrolled collapse'.[176]
During the hearing, Dr Katz identified that the temporary support structure was designed to add an additional 10 to 15% of the parapet wall's strength laterally, assuming that the existing steel straps on the dividing walls are effective. It was designed to provide an incremental increase in lateral resistance to the parapet wall in the case of wind and earthquake loading.
Dr Katz stated that the temporary support frame does not provide vertical resistance, and that if the Building moves down or the footings rotate, the frame will not restrain façade collapse. Further, Dr Katz noted there is no guarantee that the pedestrian hoarding built as part of the support frame would prevent injury or death to pedestrians in the case of façade collapse, noting his view that façade collapse is an unlikely event.
When assessing risk, Dr Katz noted that if the parking lane and footpath were closed, the consequences would be reduced. His view is that the likelihood of collapse is extremely low, that the Building is nowhere near collapse and it has a long way to go before failure occurs.
When asked in the hearing about his modelling of the structure and calculations, Dr Katz identified he had looked at whether the parapet wall could rotate on the steel beams and then used rigid body finite element analysis to model the stability of the entire section.
When modelling the parapet wall, Dr Katz had initially looked at a single section, but after he reviewed BG&E's Report, he had recalculated using the three as-built sections that Mr MacMillan identified. Under limit state loads, the façade failed, with some sections being 20 to 75% overloaded in overturning. Earthquake loading was worse than wind. Some were within safety factors but not all. Dr Katz accepted some of Mr MacMillan's concerns but noted that the temporary support structure will provide some additional support. In this case since it has not already failed, the approach would be to demonstrate why it has not failed (e.g. other load paths) and then repair it (e.g. ensuring loads can be transferred to secondary members).
For the pier analysis, Dr Katz used a working load model that assumed a footing running right to the rear of the 1.5-metre-long dividing wall section. He calculated front edge bearing pressures to the low 200s kPa (224kPa revised to 258kPa when the footing dimension as measured during the BG&E site investigation is adopted), with a triangular distribution of pressure all the way to the rear of the wall, indicating the brickwork is all in compression for the existing rotation of the structure. This did not include the earthquake load. To engage the wall in the calculation he included continuity of load through the Pritchard Francis-designed steel wall ties but noted that this is subjective since it is unclear how much these ties are engaged. He found the pier model would be stable in overturning if the façade lean was changed from 1 degree to 2 degrees.
Dr Katz described his understanding of overturning stability; he identified that instability occurs when the overturning moment exceeds the restoring moment and the centre of gravity of the structure rotates over the leading edge of the footing.
Dr Katz identified that his model and calculations have not been checked or reviewed.
Dr Katz noted that the starting point is different in determining the performance of a heritage structure versus the design of a new build. In a new design the process is to calculate a design capacity to Australian Standards prior to construction. An existing building is already standing, and the loading capacity may not be clear, the strength and behaviour of old materials may be difficult to determine. It also may not be possible to return it to an as-new condition, but it may be able to be strengthened. He noted it is not common for a client to accept a reduced capacity. Deflections may be able to be characterised as a performance tolerance rather than as a construction tolerance, which is what is prescribed in Australian Standards. An increased deflection may therefore be acceptable; however he would not advocate lower safety factors on overturning.
Dr Katz identified that in this case it is necessary to improve the foundation. The footing may need to be widened or extended inside the property boundary.
Dr Katz identified that the Building does need urgent work. His calculations have demonstrated the Building could undergo further movement, and despite the Building being in the current condition for a long time, that does not mean that there will not be incremental or steep change. Dr Katz expressed the opinion that there will be more recorded movement before failure occurs, noting that sudden failure is possible.

[210]

Mr MacMillan put forward two clear mechanisms of potential catastrophic structural failure. He utilised industry-standard, straightforward statics-based modelling methods that are foundational to structural engineering methodologies, and his modelling of the structure is, in my view, transparent, easily checked, reliable and not conservative. He identified a determinate system, which is a structure where all forces can be calculated using equilibrium equations. He made rational and industry-standard assumptions about the load path, being the transfer of the gravity loads from building element masses directly downwards through the primary elements of the Building. He calculated that the loads under the parapet wall and footings are high and acting outside the middle third as a result of the weight of the structure alone. This is sufficient to demonstrate marginal or no safety factors are present against potential collapse. Environmental loads such as wind and earthquake add to the load offset and peak bearing pressure, but Mr MacMillan did not do further calculations to include these loads because his calculations already show the Building failing under its own self-weight alone.
Dr Katz used finite element analysis modelling of the structure which, in my view, is unnecessarily complex for a determinate system and carries a correspondingly high risk of error. The way the model is constructed can lead to very different results, for example Dr Katz found that the full length of the dividing wall is acting in compression to transmit load into the foundations. This is unlikely to be true in practice because the overwhelming bulk of the mass is in the parapet wall leaning forward over the pier, and the pier at the front. Dr Katz described how he varied the soil stiffness but saw minimal impact in the model output, which indicates that his model may not respond in a realistic way to vertical displacement of the foundation or distribution of loading. When asked specifically, Dr Katz did not identify the assumptions and boundary conditions inherent in his model. Moreover, his model and calculations were not checked by any other engineer. Checking (and for critical structures, independent review) are standard industry practices, and in this proceeding, it would have greatly assisted the Tribunal to have been presented with assurance of a comprehensive check and review of Dr Katz's model and calculations, particularly given the complexity of his modelling process and reliance on secondary load paths of indeterminate capacity.
The margins of safety calculated by Mr MacMillan for both failure mechanisms show there is very little remaining buffer against collapse. A FoS of 1 means there is no margin of safety, because at this value the forces promoting a collapse are equal to the capacity of the structure to withstand them. A FoS close to 1 indicates that the applied loading is at a point that is unacceptably close to building capacity. These marginal safety factors indicate that there is such a high potential for failure and wholly insufficient protection for public safety.
Dr Katz looked at load cases with environmental loading of wind and earthquake. As part of these load cases Dr Katz identified overstress associated with the identified failure mechanisms. In order to address the 20% to 75% overload that he calculated, Dr Katz made the assumption that environmental loading would pass into secondary load paths including the rear dividing walls, the roof frame, out of plane bending of the parapet wall and the temporary support frame. This relies on the load travelling through a more convoluted load path to reach the foundations. The condition, capacity and relative stiffness of the secondary members has also not been quantified, and this would be a necessary step to ensure that the secondary members can attract and carry the load. In addition, the out-of-plane bending of the parapet wall induces significant problematic tensile stress in the brickwork and it would go against industry practice to rely on this in any way as a restraining load path. To accommodate this, Dr Katz pointed to the lime mortar used in buildings of this era and noted they were typically more flexible than modern mortars.
The temporary frame does not appear to be acting as it was designed to, since the outer bearing pads are not all hard up against the parapet wall as indicated on the drawings. I concur with Mr MacMillan and Mr MacKerron that there is likely to have been load transfer from the parapet wall into the central bays of the temporary frame and that future removal of the frame may precipitate additional outward movement at the centre of the parapet wall.
I find that the temporary frame does not provide lateral restraint to the outer sections of the parapet wall and the piers, nor does it provide vertical restraint at any level. It is therefore not an effective aid in preventing or protecting against collapse initiated through vertical movement. It may be providing sufficient restraint to prevent the parapet wall moving outwards any further, thereby restraining further outward movement of the parapet wall mass, however I concur that removing the frame may transfer additional loading into the parapet wall which may cause the tensile capacity of the masonry to be exceeded.
I concur with Mr MacMillan and Mr MacKerron that there is ample industry precedent of brittle failure of structures. The examples provided in the evidence do demonstrate that catastrophic collapse of a structure may occur at any time without warning, even after the structure has appeared to be apparently stable for many years.
I concur with Mr MacKerron that the Building is not in a state where heritage considerations may moderate the structural assessment of the Building. The façade is significantly rotated from its original as-built condition, cracking patterns provide evidence of movement from the asconstructed configuration, the roof timbers are reportedly in poor condition, there is distortion visible in the leadlight windows, cracking where the steel beams land on the piers and a brick fell through the ceiling into a tenancy. None of this has been attributed to neglect of the Building, rather the bulk of the damage can be traced back to the past excavation of the services trench and resulting compromise of the foundations.
I concur with the Applicant's engineers that the façade cannot now be pushed back to the vertical and that there are now built-in stresses in the brickwork that were not present in the as-built structure. The builtin stresses contribute to an unquantifiable but real and significant chance of collapse.
I accept that the advice from Galt is that there is no acceptable value for an allowable bearing pressure under the footings. There is no way to determine whether the soil under the footings will continue to support the footing at the current level and distribution of loading and building lean. Nor can the likelihood of downward movement or rate of settlement of the soil under the footing be quantified.
I do not give credence to the statement by Local Geotechnics that further movement was 'unlikely' due to 'reasonably expected current and transient loading conditions, and with due consideration of existing structural restraint of the piers'.[178] It is not stated what information Local Geotechnics were given about loading conditions or the extent of restraint provided by the dividing walls, but this is a structural engineering consideration and not an opinion that should be entered into by a geotechnical engineer.
I find that the foundation is highly vulnerable to excavation or soil voids adjacent to the footings, water ingress and ongoing soil consolidation, and that any one, or a combination, of these, occurring may precipitate building collapse. In addition, I find that the bearing pressures now present under the footings are higher than the geotechnical consultants have advised is allowable. The pressures have become less uniformly distributed and more concentrated on the footing leading edge, so consolidation of soil under the footings due to this load and load pattern is likely to lead to further concentration of load at an accelerated rate with a tendency for the footing to rotate outwards.
Mr MacMillan does appear to have placed great and possibly undue importance on small variations in the survey data. I find that the variations present in the survey data are not distinguishable from the station tolerance and this, combined with the small number of data points, means that any trend analysis will not be meaningful nor statistically valid. Mr MacMillan's attempt to identify a trend is perhaps understandable given the small additional movements that his calculations show may lead to progressive collapse. I find that it is unlikely that the ongoing survey monitoring is effective as an advanced warning of failure because the movement required to precipitate progressive collapse is so small and may well be indistinguishable from errors attributed to the survey tolerance.
I find that the demonstrated movement of the Building places it outside any leeway that could be provided to a longstanding structure due to undetermined material strength, secondary load paths or other unknown factors. The clear assessment of all four of the engineers is compromised safety factors. Because the failure mechanism is overturning, the strength of materials has very little bearing on whether the structure has sufficient strength. In addition, the pattern of bearing pressures of the footings onto the underlying sand has been demonstrably altered to the point there is a high load on the leading edge of the footing rather than the distributed load that would have existed before the rotation of the façade.
Overall, I consider there is a real and significant risk of collapse of the Building in its current condition. While the Building has been apparently stable, and possibly not moved significantly for many years, the risk of collapse has likely existed and possibly increased throughout the time since the building rotation was precipitated by the services trenching work in 1989. This indicates that urgent action is required to address the risk of collapse.

[212]

Both parties made submissions as to whether there are alternatives to demolition that could prevent building collapse and remediate the Building.
Dr Katz authored the list of measures that was included in the Respondent's Building Order to the Applicant. The sequence to facilitate injection grouting to stabilise the foundations was later expanded on in Tribunal proceedings by agreement between the parties. It is clear that Dr Katz has been a proponent of injection grouting but is 'all care, no responsibility' on this. He does not appear to have sufficient and relevant expertise or experience to determine whether this is a feasible option, and he confirmed in his oral evidence that this is the case.
On the other hand, Mr MacMillan does present as having the appropriate expertise and experience to specify whether injection grouting is a viable option. He has stated very clearly that it is not and provided a number of reasons including most fundamentally the potential for the injection of liquid grout to destabilise the soil under the foundations and cause loss of soil support for the heavily loaded pad footings, leading to building collapse. Other reasons include the lack of ability to determine whether the grout block has permeated the soil and extended under the footing, whether the grout block contacts the underside of the footing, the potential for the grout to ingress the services corridor and impact services and the inability to determine whether (or certify that) the actual required bearing capacity has been achieved.
My view is that Mr MacMillan's evidence strongly demonstrates that injection grouting is not an appropriate method of foundation stabilisation for the Building, and I conclude that trial grouting, whether at or remote from the pier footings, would yield inconclusive and uncertifiable results and in any case cannot be safely and reliably undertaken under the footings regardless of trial location or outcomes.
The remainder of the Building Order remediation items proposed by Dr Katz have been assessed by Mr MacMillan and I concur with his findings that many of these actions are not effective or safe to undertake. I find the Applicant was well justified in ceasing to affect the actions listed on the Building Order.
Mr MacMillan addressed a full range of remediation options in his risk assessment. Having reviewed the risk assessment and heard the evidence presented at the hearing, I conclude that the risk assessment has been carried out in accordance with industry standards and is comprehensive, including in the options it reviews which address several additional foundation stabilisation methodologies not identified by Dr Katz or Mr Marra.
Financial viability is rightly part of Mr MacMillan's method review process. Costs are commonly evaluated by engineers who carry this as a fundamental task of the practice of engineering. Engineers have a good understanding of the cost of undertaking works and as a matter of course contribute significantly or wholly to the development of estimates, tenders and bid evaluations. While the cost assessment is not the primary driver of the risk assessment per se, it would be unjust and overly onerous for the Respondent to require the Applicant to undertake a remediation measure that has been identified as cost prohibitive.
I concur with the outcomes of the risk assessment that demolition is the only option that mitigates the extreme risk identified.

[216]

In my opinion, these local planning objectives provide a good indication of what 'normal' public access might encompass. Normal access to the Building and its surrounds is certainly not available to the public at this time. The City's aspirations for the amenity of this locality are unlikely to be available until the dispute over the Building is resolved.
In my opinion, the freedom of access in front of the Building provided at various times throughout this dispute has already placed the public at extreme risk. When questioned about the temporary support frame that he designed, Dr Katz did not provide the level of confidence about public safety that would be hoped, given that he knew pedestrian access was open under the frame.
In fact, during the final hearing Dr Katz noted that the temporary support frame would be unlikely to stop injury or death in the event of bricks falling from the façade and that it was not designed to do so. In my view, there appears to have been a significant disparity in understanding about the scope and function of the temporary support frame between the City and Dr Katz. Here again, responsibility is unclear, since the Respondent's engineer designed the support frame, and the Respondent issued a Building Order requiring the Applicant install it outside their boundary over the footpath. The City asked for a support frame to support the Building[179] and its intent may not have comprehended that the frame designed by Dr Katz was designed only to withstand a small percentage of lateral environmental loads.
At the time of the site view in October 2024, public access to the front of the Building could be obtained by hopping over some waist-high barricades with insufficient warning of the danger to the public and there was full access to all road lanes.
Should a catastrophic collapse occur, the exclusion zone for demolition which was previously designed by Structerre as the Respondent's engineer to close off lanes of traffic would be the minimum extent of exclusion required to protect the public, given that demolition is a controlled event and collapse is not.
The only evaluation of risk to public safety was put forward by Mr MacMillan and, in my view, his risk assessment provides a considered and well-documented process that codifies the risk. Dr Katz noted in the hearing that he may have categorised risk slightly differently, but there was no disagreement that significant risk to the public existed.
In my view, the level of risk documented by Mr MacMillan in table 2 of his report[180] to the risk assessment inputs detailed in tables 11 to 14 are a reliable and measured assessment of the level of risk to the public.[181]
The level of risk is therefore 'extreme'.
The risk mitigation actions and residual risks as documented by Mr MacMillan in table 2 of his report are, in my opinion, a reliable and measured assessment of the possibility and outcomes of risk mitigation.[182]
Therefore, in my view, the only viable option identified that mitigates the extreme risk to public safety is demolition.

[217]

No evidence was presented to the Tribunal on where responsibility lies in terms of risk mitigation for the Building. Should the Building collapse and have a human toll or cause damage, I ask the parties to carefully consider who is liable in this situation?
The Applicant has been consistent in its assessment that there is a danger to public safety and that the Building should be demolished, in addition to their advocacy for the continuation of extensive access restrictions.
Similarly, in the case of grouting trials ordered by the City, there is no indication of who would be liable for any mishap. The Applicant, having been advised of the risks by their engineer, has refused to proceed with the trials and there the matter has stalled.
Item 18(a) of the Table in cl 61(1) addresses cases such as this one, where there is a credible and demonstrated risk to public safety. It deliberately bypasses development approval such that demolition can occur prior to any review of any proposed development for the site. Refusal of a demolition permit on these grounds is therefore a moot point - what should have been properly and thoroughly assessed by the Respondent in its consideration of this demolition application is therefore the urgent need to demolish for public safety.
There has been no evidence presented that the Respondent has given more than a cursory consideration to the evidence of ARUP, BG&E or indeed its own engineer Structerre. The Respondent has engaged Dr Katz through Quoin and then Keystone Structural, in line with its policy to engage its own engineering advice. However, the City does not appear to have sought to seriously analyse the chasm between the expertise and opinions of these professional engineers, even when this was strongly supported by the accompanying letter from the WAPC on 28 September 2022.[183] The review by Mr Marra was not commissioned until the work leading to the July 2024 Engineering Design Consultancy (EDC) report in the lead-up to this hearing, and even that report does not serve to bridge the gap.
In its minutes and public announcements, the City has referred to Dr Katz's advice as the 'latest engineering advice', as though it supersedes all previous engineering advice. In my view, this downplays this very serious matter and dismisses the significant work and weighty opinion submitted to it for its consideration. Such consideration should be done with due and proper process, appropriate acknowledgement and mitigation of bias and risk, be documented and communicated to the Applicant.
In my view, public safety is likely to be at greater risk if the Respondent continues to push for building works, injection grouting trials and additional propping, due to a false sense that these measures will be effective and facilitate safe public access.
If anything, the City's complacency and lack of due consideration of all the engineering advice has endangered public safety.

SANUR PTY LTD and CITY OF SUBIACO [2025] WASAT 107 (7 October 2025)

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SANUR PTY LTD and CITY OF SUBIACO [2025] WASAT 107 (7 October 2025)