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1 In these reasons, a reference to “ACAT” or the “tribunal” refers to the ACT Civil and Administrative Tribunal generally, whereas “Appeal Tribunal” or “Tribunal” refers to the presently constituted tribunal. When discussing the first instance decision, the Tribunal uses the expressions “Original Proceedings”, “Original Decision(s)”, and “Original Tribunal” 2 Transcript of hearing dated 10 October 2025, page 30, lines 18-19

5. In the appeal proceedings, Mr Mitchell continues to seek a “pathway to 3 certification”. Formally, however, he contends that the order of the Original Tribunal should be set aside and replaced with an order requiring the respondent to pay him compensation in the sum of $25,000.

A preliminary issue: proper identification of the respondent

6. Before the Original Tribunal, the respondent to Mr Mitchell’s application was 4 identified as “Don Waring trading as Construction Management Studio Pty Ltd”. The respondent was identified in the same way in the final order made by the Original Tribunal.

7. A natural person can carry on business as a sole proprietor, and for that purpose can utilise a trading name. Likewise, a corporation may use one or more trading names, different from its registered corporate name, for the purpose of carrying on its business activities. An individual cannot, however, “trade as” a company, nor vice versa. Although Mr Mitchell’s Civil Dispute Application included reference to an Australian Business Number (ABN), it was never clarified in evidence before the Original Tribunal whether that ABN was associated with Mr Waring carrying on business in his own name, as a sole proprietor, or with a company named Construction Management Studio Pty Ltd.

8. All of the evidence presented to the Original Tribunal suggests that the proper respondent to the proceedings initiated by Mr Mitchell was Mr Waring, the individual, not any corporate entity. In addition, it appears that the whole of the proceedings was conducted on the basis that the respondent was, in fact, Mr Waring personally. By way of example: (a) on the evidence, email correspondence which led to the formation of the contract for certification services was signed off as “Don Waring” or “Sandra Zak for Don Waring”, without any reference to “Construction Management Studio Pty Ltd” (or any other company name);

3 See e.g. “Submissions” annexed to Application for Appeal lodged on 14 November 2025 at [20] 4 The ACT Government was initially identified as a second respondent to the proceedings but as explained below, successfully applied to be removed from the proceedings (b) plans relating to the Building Project were approved and stamped in the name of “Don Waring” — not as “Construction Management Studio Pty Ltd”; (c) the “Response” lodged with the Original Tribunal was submitted in the name of “Don Waring”, without any reference to “Construction Management Studio Pty Ltd”; (d) the transcript of the hearing before the Original Tribunal indicates that the name “Construction Management Studio Pty Ltd” was not mentioned at any point; and (e) the Tribunal’s files indicate that no “Authority to Act” on behalf of Construction Management Studio Pty Ltd was ever requested by the Original Tribunal nor furnished by Mr Waring.

9. It may be the case that, at the relevant time, Mr Waring’s commercial arrangements in some way also involved a company known as Construction Management Studio Pty Ltd. If so, it appears that Mr Waring did not regard that entity as having any relevance to the proceedings before the Original Tribunal. Mr Waring has never suggested that he personally was not the proper respondent to Mr Mitchell’s proceedings.

10. Written submissions lodged with the Appeal Tribunal for the purpose of the appeal identified the respondent as “Don Waring”. Mr Waring appeared on his own behalf at the appeal, as he had at the hearing before the Original Tribunal.

11. Accordingly, the first order which the Appeal Tribunal will make is to amend the name of the respondent to “Donald John Waring”. References to “the respondent” hereafter should be understood accordingly.

The proceedings before the Original Tribunal

12. The Civil Dispute Application which Mr Mitchell lodged with the Original 5 Tribunal was designated by him as a “Contract Application”. Initially, the

5 “Contract application” is defined in s 15 of the ACT Civil and Administrative Tribunal Act 2008 to mean “an application in relation to a contract and includes an application for damages for breach of contract” application identified two respondents, “Don Waring trading as Construction Management Studio Pty Ltd” and “ACT Government (Access Canberra)” (the Territory). The amount claimed, to begin with, was $86. Mr Mitchell indicated that he also sought “[a] direction jointly to Don Waring and the ACT Government 6 to determine a pathway to certification”.

13. Mr Waring responded to the application on 12 June 2025, indicating that he had retired from certification work and that, in December 2025, arrangements had been made for another certifier, Mr John Bates, to take over his role in relation to the Building Project. This appears to have been an attempt to “wash his hands” of the matter.

14. At a directions hearing on 26 June 2025, the Territory successfully applied to be removed as a party to the proceedings. The Tribunal accepted the Territory’s contentions that it was neither a party to the contract between Mr Mitchell and Mr Waring, nor had it made any reviewable decision leading to the non-renewal of Mr Waring’s licence as a certifier.

15. Directions were made to progress the matter to hearing, including for Mr Mitchell to file an amended application setting out the final orders which he sought. In a bundle stamped 15 September 2025 and treated by the Original Tribunal as an 7 amended application, Mr Mitchell claimed that: (a) Mr Waring had failed to provide the certification services for which he was engaged; (b) to the extent that Mr Waring did any certification work, the steps which he took were either completed incorrectly or did not assist in progressing the Building Project towards certification; (c) as a result, Mr Mitchell had suffered losses totalling $33,473; and

6 See Civil Dispute Application lodged on 7 April 2025 in proceedings XD 458 of 2025 7 Mr Mitchell contended that this bundle was in fact lodged with the Tribunal prior to 8 September 2025 (d) Mr Mitchell sought an order requiring Mr Waring to pay him the maximum amount able to be awarded in civil proceedings in the tribunal, namely, $25,000.

16. Mr Waring did not lodge an amended response with the Tribunal. On 8 September 2025, however, he sent three emails with attachments to the Tribunal entitled 8 “Additional Documents found” (or similar). This appears consistent with his non-committal approach to the proceedings.

17. At the hearing before the Tribunal on 10 October 2025, Mr Mitchell itemised his losses as follows: (a) the full amount of the certification fee paid to Mr Waring in March 2023, being $3,300; (b) the cost to Mr Mitchell of obtaining an engineering design certificate, being $1,980, and then a further $330 for an updated certificate; (c) “fees paid to Kelvin Guo in the sum of $7,000”; (d) rates paid to the ACT government in about September 2024, apparently for the period October 2024 to July 2025, in the sum of $4,261; (e) “the cost of insurance in the sum of $4,650”; (f) a fee paid to “ACT Certification Services” in the sum of $1,452; (g) the cost of obtaining a final engineering certificate in January 2025, in the sum of $550; and (h) “the anticipated cost of obtaining updated building plans in the sum of $10,000”.

18. The hearing before the Original Tribunal proceeded, on 10 October 2025, as a multi-party discussion of the various issues, without witnesses being sworn and without any record being made of what documentary material was taken into evidence. This approach is consistent with the emphasis on informality and flexibility reflected in sections 7, 23 and 26 of the ACT Civil and Administrative Tribunal Act 2008 (ACAT Act) but can make the role of the Appeal Tribunal

8 The content of the attachments to these emails is discussed further below more challenging. Mr Waring was assisted at the final hearing by Mr Ken Hopkins, a person whom Mr Waring put forward as an expert in certification issues under the Building Act 2004. It appears that, part way through the hearing, Mr Waring produced a copy of architectural plans for the prefabricated house which, by necessary inference, must have been supplied to him at some earlier time. Unfortunately, those plans were not exhibited nor retained by the Tribunal and cannot now be located.

19. Ultimately, Mr Waring did not dispute many of the factual matters asserted by Mr Mitchell. He did, however, oppose the outcome sought by Mr Mitchell. With the assistance of Mr Hopkins, Mr Waring submitted among other things that, as a licensed owner builder, Mr Mitchell bore at least as much responsibility as Mr Waring for the building work related to, and progress of, the Building Project.

Decision of the Original Tribunal

20. The Original Tribunal ordered Mr Waring to pay Mr Mitchell the sum of $1,320, being a refund of 40% of the fee which Mr Mitchell had paid to Mr Waring in March 2023 for his anticipated work as a certifier in relation to the Building 9 Project. By inference, the Original Tribunal found that the work carried out by Mr Waring was worth 60% of the fee he had been paid.

21. The Tribunal disallowed all of the consequential losses claimed by Mr Waring.

22. The Original Tribunal did not identify nor analyse any particular cause of action as part of its determination Mr Mitchell’s application. The Original Decision appears rather to have been based on an analysis of the responsibilities imposed on a licenced owner builder by the Building Act 2004. The following passage, in particular, reflects the reasoning process of the Original Tribunal: The legal position is that the applicant, being the owner and the builder, is responsible for all aspects of the build and cannot delegate that responsibility. That is, the owner-builder is responsible for all that happens on the site, for engaging all the contractors and ensuring that all work complies with the Building Act and managing the issues that arise. This

9 It needs to be observed that the Original Tribunal expressed considerable sympathy for the difficult and unusual situation in which Mr Mitchell found himself, but (rightly) took the view that it was constrained in terms of the orders which it could make in relation to his civil application includes obtaining building approval for the project before starting. [Mr Mitchell] is therefore responsible for the fact that the plans that had been approved were not for the house that he was in the process of building.

23. The above analysis is undoubtedly correct as a description of the scheme of the Building Act 2004. It may also be an accurate description of Mr Mitchell’s potential liability to third parties in respect of the quality and progress of the building work which occurred at the Site. Generally, as a licenced owner builder, at least as far as third parties are concerned, Mr Mitchell bore as much responsibility as Mr Waring.

24. As an analysis of the contractual relationship between Mr Mitchell and Mr Waring however, what the Original Tribunal stated is insufficient. As part of his commercial engagement by Mr Mitchell, Mr Waring had a contractual obligation to exercise professional skill and competence. As will be discussed further below, this proposition is ultimately critical in terms of the outcome of the appeal.

The appeal

25. In written submissions, Mr Mitchell asserted that the Original Tribunal made 15 errors, comprising a combination of errors of fact, “errors of procedural fairness”, an error of law, and several errors which Mr Mitchell described as 10 “incompetence”. There is considerable overlap in Mr Mitchell’s discussion of the various alleged errors, and some of what he has asserted is difficult to understand.

26. Five key allegations can be distilled from the submissions advanced by Mr Mitchell: (a) a complaint that the role played by Mr Hopkins at the hearing before the 11 Original Tribunal was unfair;

10 “Submission by Appellant” filed on 20 February 2026 11 See Mr Mitchell’s Issue 15 (b) an allegation that the Original Tribunal unfairly accepted or incorrectly analysed the copy of the architectural plans only produced by Mr Waring 12 during the actual hearing; (c) an allegation that the Original Tribunal incorrectly analysed, or gave insufficient weight to, evidence of a lack of professional competence on the part of Mr Waring, including: (i) the undisputed evidence that Mr Waring approved out-of-date plans for the construction of a straw-bale-house instead of the plans for a prefabricated house; and (ii) evidence of irregular inspections carried out by Mr Waring and associated irregular or fraudulent inspection reports, including Mr Waring’s failure to provide copies of the reports at the time either 13 to Mr Mitchell or the ACT Government; (d) an allegation that the Original Tribunal incorrectly analysed, or gave insufficient weight, to evidence suggesting that Mr Waring had forged documents, in particular a “Change of Certifier” form dated 15 December 14 2023; and (e) a general allegation that the Original Tribunal erred by failing to accept evidence of losses incurred by Mr Mitchell as a consequence of Mr Waring’s lack of competence and/or dishonesty in discharging his 15 duties as a certifier.

27. For convenience, although it involves a departure from the submissions made by Mr Mitchell, I discuss Mr Mitchell’s various complaints regarding the Original Decision by reference to the above five allegations.

Test for appeal

28. An appeal within the Tribunal may be dealt with either as a review of the decision of the Original Tribunal, or as a new application. At a directions hearing on

12 See Mr Mitchell’s Issue 2 13 See Mr Mitchell’s Issues 1, 3, 5, 7, 9, & 10 14 See Mr Mitchell’s Issues 3, 6 & 7 15 See Mr Mitchell’s Issues 4, 12 & 14 10 December 2025, the Appeal Tribunal directed that the appeal should proceed as a review of the decision of the Original Tribunal unless otherwise ordered. At the hearing of the appeal on 10 April 2026, I determined that it was appropriate to maintain this approach.

29. In order to succeed on an appeal in the nature of a review, the appellant must 16 establish an error of fact, law or discretion which was material to the result. In 17 addition: (a) ordinarily, if there has been no further evidence admitted or no relevant change in law, an appeal tribunal can exercise its appellate powers only if satisfied that there was an error on the part of the original tribunal; (b) the appellate tribunal will give proper allowance to the advantage of the original tribunal who saw and heard the witnesses, so that, ordinarily, facts found based on the assessment of witnesses will not lightly be overturned; (c) the appeal tribunal is obliged to conduct a real review of the trial and the reasons of the original tribunal; (d) in an appeal by way of rehearing, once error below has been found (after making proper allowance for the advantages of the original tribunal), the appeal tribunal can substitute its own decision based on the facts and the law as they now stand.

Evidence

30. In the appeal, I had regard, first, to all of the evidentiary material before the Original Tribunal, which comprised: (a) documentary material relied on by Mr Mitchell, including: (i) documents appended to Mr Mitchell’s application; (ii) documents which formed part of a bundle treated by the Original Tribunal as an “amended application”;

16 See for example Zeng v Crane [2022] ACAT 70 at [27] and Feng v UP 840 [2023] ACAT 8 at [7] 17 V v Elringtons Pty Ltd [2018] ACAT 23 at [23], as cited in He v Qin & Ors [2021] ACAT 129 at [43] (b) documents emailed to the Tribunal by Mr Waring on 8 September 2025 (Mr Waring sent three emails to the Tribunal, each with attachments, on that date); (c) plans produced by Mr Waring at the hearing (which, as I have noted, unfortunately were not retained by the Tribunal but which are described in the transcript of the hearing before the Original Tribunal); (d) documents produced under subpoena by “Trone Projects”, a construction management company engaged at one point by Mr Mitchell in relation to the Building Project (see below); (e) assertions of fact made by Mr Mitchell orally in the course of the discussion 18 of the various issued before the Tribunal; (f) assertions of fact made orally by Mr Waring in the same way; and (g) some assertions of fact made by Mr Hopkins.

31. Secondly, at the hearing of the appeal, I granted leave to Mr Mitchell to adduce limited fresh evidence comprising: (a) an analysis by Mr Mitchell of documents provided to the Original Tribunal by Mr Waring (which Mr Mitchell claimed were forgeries) and associated statutory declarations by Mr Mitchell; (b) some uncontentious background evidence, not objected to by Mr Waring, which identified the “straw bale house” plans originally approved by Capital Certifiers, and a building approval and inspection records issued by Capital Certifiers prior to their withdrawal from involvement in the project (see below).

Factual background

32. As I have already noted, Mr Waring’s approach to the proceedings before the Original Tribunal involved relatively little contest on his part as to many factual matters, although overall he denied contractual liability to Mr Mitchell. The

18 As is the case with many proceedings before the Tribunal, the parties’ respective “submissions” involved the intermingling of both factual assertions and arguments as to the facts and applicable law following matters, which it is appropriate to set out at some length, emerged as largely uncontentious. Areas of disputation have been highlighted.

33. Mr Mitchell is a qualified engineer with about 40 years’ professional 19 experience. He is a Fellow of Engineers Australia. In about 2019, Mr Mitchell resolved upon a knockdown-rebuild project in relation to the Site. The initial plan was that the new residence would be a straw-bale house. Plans were drawn up in 2019 by an architectural firm, “reimagined habitat”, and refined in 2020. Mr Stephen Monkhouse of Capital Certifiers Pty Ltd was engaged as a certifier and approved the “straw-bale-house” plans. Building approval number B20201544 was issued.

34. Building work commenced in 2020. Mr Monkhouse carried out inspections in December 2020 and May 2021, at the footings and pre-slab stages. At this point, the COVID epidemic intervened. For reasons which are not entirely clear, Mr Mitchell “pivoted”, abandoning the plan for a straw bale house in favour of construction of a prefabricated residence, the components of which were to be imported from Poland. Mr Mitchell entered into a contract with an importer in October 2021. In April 2022, “reimagined habitat” drew up a revised set of plans, marked “For Client Approval” (April 2022 Revised Plans).

35. At around this point, Mr Monkhouse withdrew from involvement in the Building Project. Mr Mitchell was proceeding with the imported prefabricated house as an owner builder. It appears Mr Monkhouse’s professional insurance may not have extended to this type of endeavour.

36. Mr Mitchell contacted Mr Waring, and they arranged to meet at the Site on 17 March 2023. Mr Mitchell expressed concern that the approval previously issued by the ACT Government (in respect of the plans for a straw-bale house) was due to expire and was anxious, if possible, to avoid having to pay a second building approval fee. Mr Waring advised Mr Mitchell by email that, provided Mr Waring formally took over as certifier prior to 13 April 2023, the government

19 Mr Mitchell is now working only part-time. He explained that the stress associated with several sets of legal proceedings relating to the Building Project was one of a range of factors which had necessitated a reduction in his work hours fees paid on 16 April 2020 would “remain valid”. Mr Waring advised Mr Mitchell that once he (Mr Waring) was appointed as certifier, “the original BA will be re-approved from the point that the original Certifier stopped and I started” (emphasis added).

37. On 27 March 2023, Mr Waring provided a written quote to Mr Mitchell in respect of the following proposed work (emphasis added): Re-approval of Project B20201544 (from 14/4/23) • Floor Slab to Final: New Residence • Part Demolition: Existing Dwelling • Pond over Garden Structure

38. The quotation was for $3,300 (inclusive). Mr Mitchell paid the full amount immediately, in advance. An “Appointment of a Certifier” form marked “Change of Certifier”, appointing Mr Waring as certifier for the balance of the Building Project, was executed by Mr Mitchell and his wife on 14 April 2023 (First Change of Certifier Form). There was no separate written contract.

39. There is a dispute about whether, at the meeting on 17 March 2023, Mr Mitchell provided Mr Waring with a copy of the April 2022 Revised Plans. Nonetheless, Mr Waring agrees that from this early stage he was aware that Mr Mitchell had in fact abandoned the plan for a straw-bale house in favour of the proposed prefabricated residence from Poland.

40. On 5 May 2023, Mr Waring re-stamped, as “approved”, the plans for the straw-bale house which had previously been approved by Mr Monkhouse — in fact, both the Capital Certifiers stamp’ and Mr Waring’s stamp are visible on the version of the plans tendered in evidence before the Original Tribunal. Also on 5 May 2023, Mr Waring: (a) signed a “Site Work Notice” certifying that “the plans for the building work to which the application for building approval relates show all the information necessary to establish that the site work is exempt development under the Planning and Development Act 2007”; and (b) signed a “Building Commencement Notice” for the purposes of the Building Project, indicating that the building work to be undertaken included “Completion of Extension and Alterations, Slab to Final (Class 1a)” and “Pergola & Deck (Class 10a)” at an estimated cost of $1,000,00 [sic].

41. Mr Waring communicated his “approval of plans” by phone to Mr Mitchell. Mr Mitchell claimed before the Original Tribunal that he did not realise that what Mr Waring had done was to re-approve the plans relating to the straw-built house. Building Approval number 20231634 (B20231634) was issued.

42. In the meantime, on 24 May 2023 Mr Mitchell emailed Mr Daniel Grobezny, who was responsible for importing the prefabricated house, requesting that Mr Grobezny provide an engineering certificate for the revised Building Project. Mr Mitchell indicated that the certificate was urgent, to enable work with “the building components” to commence. Mr Waring was copied into the email. 20 Mr Grobezny did not respond. Mr Mitchell then engaged a Mr Jihad Shalak, of “Gilcon Structural Engineers”, to provide the required engineering certification.

43. On 1 June 2023, Mr Waring emailed Mr Mitchell, this time attaching the Building Commencement Notice he had executed on 5 May 2023 and “Approved Plans”. Mr Mitchell says that it was only at this time that he realised that Mr Waring had in fact re-approved the superseded plans for the straw-bale house. Mr Mitchell told the Original Tribunal that he raised concern about this fact with Mr Waring over the phone on several occasions and was told by Mr Waring that the issue of approving the correct plans could be “fixed up” at a later stage.

44. On 16 June 2023, Gilcon Structural Engineers issued a structural certificate in respect of the revised Building Project. Mr Shalak forwarded the certificate to Mr Mitchell on 18 June 2023, who in turn forwarded it to Mr Waring on the same day.

45. On 20 June 2023, a subcontractor working for Mr Mitchell, Mr Spencer, requested Mr Waring to attend the Site to carry out a “point of inspection”. Mr Spencer appears to have been concerned to ensure that the steps towards

20 Mr Mitchell advised the Appeal Tribunal that at some point Mr Grobezny “did a runner” and that there are separate legal proceedings on foot relating to the importation process construction of the prefabricated house which had been undertaken to date were both structurally sound and “okayed” by the certifier. There is nothing to suggest that Mr Spencer was aware of any impediment to the further progress of building work, such as the lack of approved plans relating to the proposed prefabricated residence.

46. Mr Waring attended the Site on 22 June 2023. He filled out and signed a “Building Inspection Record” in relation to what he described as “Inspection of thermacell removal & frame” which: (a) noted that sheets pre-installed on the prefabricated walls had to be partially disassembled to allow access to examine the framing; (b) the walls were “generally compliant”; (c) certified that “the building work has been generally constructed in accordance with the approved plans” (even though the only plans which Mr Waring had approved at this stage were for construction of a straw-bale house); and (d) gave permission for further building work to proceed (22 June Inspection Record).

47. Mr Waring did not provide a copy of the 22 June Inspection Record either to Mr Mitchell or to the ACT Government. Its existence was not known to any third party until Mr Waring emailed it and other documents to the tribunal, as “Additional Documents found”, on 8 September 2025.

48. On 26 June 2023, “reimagined habitat” issued a revised set of architectural plans for the Building Project marked “for construction”.

49. On 23 June 2023, Mr Mitchell engaged “Trone Projects” to project manage the Building Project. The principal of Trone Projects is a Mr Kelvin Guo. Mr Mitchell was then away overseas (and therefore unable to directly manage the Building Project himself) between about July 2023 and September 2023.

50. On 3 July 2023, “reimagined habitat” issued a further revised, and apparently final, set of architectural plans for the Building Project, again marked “for construction”.

51. On 7 July 2023, Mr Waring carried out another inspection at the Site. Again, it seems, he filled out and signed a “Building Inspection Record” in relation to what he described as “Wall Frame – Upper Level” which: (a) identified the relevant “Approved Plan No.” as “B20231634 & 20201544”; (b) noted “ground floor framing generally completed”; (c) noted in relation to the “upper floor” that “floor framing with beams & Floor joists all as per structural details with some supplementary timbers”; (d) noted that “Wall & roof framing generally completed as detailed also with some supplementary timbers to suit”; (e) again, certified that “the building work has been generally constructed in accordance with the approved plans”; and (f) gave permission for further building work to proceed (7 July Inspection Record).

52. Again, Mr Waring did not provide the 7 July Inspection Record to Mr Mitchell nor to the ACT Government. Its existence was only disclosed to third parties when he emailed it to the tribunal on 8 September 2025.

53. Building work appears to have continued between July and September 2023. There were still no approved plans in place relating to the prefabricated residence during this period.

54. Sometime in September or October 2023 (the precise date is not clear from the evidence presented to the Original Tribunal), Mr Waring was advised by his insurer that his professional indemnity insurance would not, for now, be renewed. Apparently this was because of historical complaints about Mr Waring from some of his former clients. The ACT Government apparently allowed Mr Waring until 31 October 2023 to finalise his certification activities, after which point, because he no longer had insurance, his licence as a certifier would lapse.

55. Mr Waring did not advise Mr Mitchell that he was about to lose his certification licence.

56. Mr Waring’s email to the tribunal on 8 September 2025 included a third and final “Building Inspection Record” dated 3 October 2023 (3 October Inspection Record) as well as an extract from his diary of that date indicating he attended the Site for the purpose of a “Pre-Sheet Insp?” [sic]. The Record describes the inspection stage as “Nominal ‘Presheet’ for Prefab system” and further records: Container, Imported, prefab, 2 storey Home. • The container contains a preassembled, flat pack roof, walls & upper floor etc. • This Inspection does not include any of the ancillary structure. • I find the ‘work’ to be generally suitable/compliant, based on my previous work on a 2 storey home. • There are still a significant amount of amended construction changes that all require formal Amendments as detailed drawings. These need assessment approval, submission to government & fees paid. The following information must be provided: All ‘Amendments’ to original BA Approvals.

57. The content of the 3 October Inspection Record is curious for a number of reasons which I identify later in these reasons.

58. It is common ground that, as with the other Inspection Records, Mr Waring did not provide a copy of the Record at the time either to Mr Mitchell or to the ACT Government. On the evidence before the Original Tribunal, Mr Waring’s “non-approval” of further building work was not communicated to anyone.

59. Mr Mitchell appears to have been back in Australia and re-engaged in relation to the Building Project by mid-October 2023. On 19 October 2023, at Mr Mitchell’s request, Gilcon Structural Engineers provided an updated engineering design certificate.

60. Mr Waring’s licence as a certifier lapsed on 30 October 2023. Mr Waring did not communicate that fact to Mr Mitchell. Critically, at the time, Mr Waring still had not approved a set of plans relating to the prefabricated house. The only set of approved plans related to the now well-outdated straw bale house.

61. On 8 December 2023, Mr Mitchell received an email from Access Canberra, which came as a surprise to him, advising that Mr Waring was no longer licensed to operate as a building certifier in the ACT, and that he (Mr Mitchell) would be required to locate and engage a new certifier to complete the building works at the Site. Mr Mitchell contacted Mr Waring urgently. A meeting on Site with Mr Waring and another certifier, Mr John Bates, was arranged for 14 December 2023. Mr Bates attended on that date carried out some form of inspection of the Site. Mr Waring informed Mr Mitchell that Mr Bates would take over the certification work for the Building Project.

62. On 22 December 2023, Mr Waring sent an email to Access Canberra attaching an “Appointment of a Certifier” form marked “Change of Certifier” (Second Change of Certifier Form). On its face, the Second Change of Certifier Form had been signed by Mr Mitchell on 15 December 2023 and was effective to appoint Mr John Bates as certifier for the remainder of the Building Project. The Territory processed the change of certifier, on the assumption that the Second Change of Certifier Form was authentic, in early 2024.

63. Mr Mitchell presented evidence to the Original Tribunal which indicated that, in January and February 2024, he repeatedly attempted to contact Mr Waring to find out when Mr Waring was going to do the “paperwork” to effect the change of certifier. Later, in April 2024, Mr Guo on behalf of Mr Mitchell contacted Mr Bates to attempt to arrange a final inspection for the Building Project, which by that time was approaching readiness for the issue of a Certificate of Occupancy.

64. No progress on the stalled Building Project occurred during 2024 or the early part of 2025. In that context that, on 7 April 2025, Mr Mitchell lodged his Civil Dispute Application with ACAT.

65. On 25 July 2025, the Territory formally issued a stop work notice in respect of the building work at the Site, on the basis that building work was being carried out “carried out contrary to a provision of Act”.

66. At the hearing before the Original Tribunal in October 2025, Mr Mitchell contended that he had never signed Second Change of Certifier Form. He asserted that, at the time, he was entirely unaware that any such document had been created or lodged with and accepted by the Territory.

Consideration of appeal Preliminary observations regarding the facts

67. Before turning to consider the five key allegations distilled from Mr Mitchell’s submissions on the appeal, it is appropriate to make some preliminary observations regarding the circumstances associated with Mr Waring’s involvement in the Building Project and regarding some of the factual matters which were disputed.

Why Mr Waring re-approved the superseded straw-bale-house plans

68. Mr Waring was at a loss, both at the hearing before the Original Tribunal and before the Appeal Tribunal, to explain why in May 2023 he approved the superseded plans for the straw bale house, rather than adopting some other course. He suggested, for example, that at that time he had not received any plans for the proposed prefabricated house — a position which Mr Mitchell vigorously disputed (Mr Mitchell was insistent that he had handed Mr Waring a copy of the April 2022 Revised Plans at the meeting on 17 March 2023). At other times, Mr Waring contended that, as at May 2023, he had not received any version of plans for the prefabricated house capable of being approved (Mr Waring emphasised, for example, that the April 2022 Revised Plans were marked “for client” and asserted that he was therefore entitled to disregard those plans).

69. It is undeniable that part-way through the hearing before the Original Tribunal, Mr Waring produced a set of plans which the parties identified as being the April 21 2022 Revised Plans. That set of Plans must have been provided to Mr Waring by someone. He was unable to explain who had provided the Plans to him, or when.

70. At the Appeal Hearing, Mr Waring explained that he is presently in his seventies and is experiencing some health issues which may be affecting his mental capacity. Mr Waring also disclosed that the period immediately before and after the cancellation of his certifier’s licence was chaotic — he made reference to

21 Transcript of hearing dated 10 October 2025, pages 39 to 41 22 having “a half thousand files” in his double garage, as well as some files stored at the premises of a former business colleague.

71. Putting all these pieces together, I am satisfied that the most likely reason for Mr Waring having approved the straw-bale house plans in May 2023 is the 23 explanation which is reflected in the contemporaneous documents, namely, that Mr Waring had told Mr Mitchell that this is exactly what he would do in order to allow Mr Mitchell to avoid having to pay a second building approval fee. It matters not that Mr Mitchell failed to understand the import of the email which Mr Waring sent him on 27 March 2023, nor that, by the time of the hearing before the Original Tribunal in October 2025, Mr Waring had forgotten this was the reason why he had approved that set of plans. Mr Waring was not on a strange frolic of his own. Whether wisely or not, he was endeavouring to assist Mr Mitchell.

72. Ultimately, this conclusion on the facts is not critical in resolving the issues raised in the appeal. It is, however, relevant and important, in explaining what might otherwise appear to be inexplicable conduct of Mr Waring.

The undisclosed inspection records

73. I have noted above that, in a departure from normal practice, Mr Waring did not provide copies of any of the three inspection records he says he created as a result of inspections at the Site in 2023 either to the owner of the property, Mr Mitchell, nor to the ACT Government. The first time those records were disclosed to any third party appears to have been when Mr Waring sent them by email, with other documents, to the tribunal in September 2025.

74. The existence and content of each of the inspection records is significant, albeit for varying reasons. As to the 22 June Inspection Record and the 7 July Inspection Record, these are significant because they were created at a time when Mr Waring must have known that what he was inspecting was a partially prefabricated residence. The content of the records further provides compelling evidence that,

22 Transcript of hearing dated 10 October 2025, page 63, line 46 23 I bear in mind the observations of Gleeson CJ, Gummow & Kirby JJ in Fox v Percy [2003] HCA 22 at [31] regarding the significance to be attached to “contemporary materials, objectively established facts and the apparent logic of events” as contended by Mr Mitchell, even if Mr Waring did not hand over the actual inspection records, he nonetheless gave every indication that he approved the continuation of building work, notwithstanding there were no approved plans for a prefabricated house.

75. The significance of the 3 October Inspection Record is different. This record, if it was indeed made on 3 October 2023, was possibly created after Mr Waring had learned from his insurer that his professional insurance was not to be renewed. Its content is both different from the content of the other two inspection records and curious in that: (a) the first part of the Record seems to suggest that, at the time of inspection, no building work at all had been undertaken and that the “prefabricated house” was still in a flat pack inside the container in which it had arrived — obviously this is inconsistent with the stage which the building work at the Site had reached by 3 October 2023; (b) unlike the previous two inspection records, Mr Waring indicates in this record for the first time that there are outstanding drawings, approvals and government fees which need to be resolved and only a qualified view that relevant building work might be capable of being approved; (c) also, for the first time, Mr Waring indicates that building work cannot continue until “corrective action” is undertaken; and (d) the handwriting on the record appears to be of varying thicknesses in different sections of the Record (the other Inspection Records had the same handwriting thickness throughout).

76. One possible argument about the 3 October Inspection Record is that, unlike the other two inspection records, it is a self-serving document created, or possibly edited, by Mr Waring with the intention of trying to protect himself from the consequences of having allowed months of building work on an unapproved structure to proceed. This interpretation might explain why the record inexplicably refers, in October 2023, to the components still being in the flat packs in which they arrived, and why there is for the first time a reference, never communicated to any other person, to a need for amended plans to be submitted and approved.

77. The unusual features of the 3 October Inspection Record were not explored before the Original Tribunal, and the reasons of the Original Tribunal give little if any consideration to its content. Mr Waring was not cross-examined on it (as I have noted, no formal cross-examination of any witness was undertaken).

78. In the circumstances, it is neither feasible nor safe to reach conclusions about the authenticity of the 3 October Inspection Record. Fortunately, it is not necessary to do so in order to be able to dispose of the appeal.

79. I turn then to consider each of the five issues identified as having been raised by Mr Mitchell.

Ground 1 — the role played by Mr Hopkins before the Original Tribunal was unfair

80. On 29 September 2025, Mr Waring lodged an application for interim orders with the Tribunal, seeking approval for Mr Hopkins “to provide information (as required) to all parties” at the hearing. The application asserted that Mr Hopkins was “an Expert in the ACT Building ACT of 2004” (the current applicable legislation for Licenced Private Certifiers & Licenced Builders). Determination of the application was deferred until the commencement of the hearing before the Original Tribunal.

81. Mr Hopkins attended the hearing, but his role appears never to have been clarified. The transcript of the Original Hearing indicates that Mr Hopkins indeed provided “information” to the Tribunal, agreed with certain statements made by Mr Waring, raised questions with and challenged Mr Mitchell as to certain matters, and made submissions to the Tribunal, including as to the level of responsibility which Mr Mitchell was obliged to accept in relation to the building work at the Site as a licensed owner builder.

82. The role played by Mr Hopkins was somewhat unusual. It is plausible that, at times, Mr Mitchell may have been flustered at being challenged by Mr Hopkins as well as having to answer questions from the Tribunal.

83. Unlike a Court, the Tribunal is at liberty to determine its own procedures, and its procedures are to be as informal and flexible as is consistent with the dictates of 24 justice. It would have been better if the reason for Mr Hopkins’ presence and his role had been clearly defined from the outset, but I am not satisfied that, by itself, the role played by Mr Hopkins involved error on the part of the Original Tribunal, nor that it irredeemably affected the fairness of the proceedings.

Ground 2 — unfair acceptance/incorrect analysis of documents irregularly produced by Mr Waring for the first time at the hearing

84. I understand Mr Mitchell’s complaint in this regard to relate primarily to the version of the April 2022 Revised Plans apparently produced by Mr Waring in 25 the course of the hearing before the Original Tribunal on 10 October 2025, but also to the inspection records emailed to the Tribunal and disclosed to Mr Mitchell for the first time in September 2025.

85. It is troubling, as Mr Mitchell contends, that notwithstanding Mr Waring had earlier been served with a subpoena to produce all documents in his possession relevant to the proceedings, his copy of the April 2022 Revised Plans was only produced during the hearing. Mr Waring did not offer any explanation for his failure to produce the Plans in response to the subpoena, other than that because the April 2022 Plans were marked “for client approval” he probably disregarded them.

86. At the Appeal Hearing, Mr Waring explained that his copy of the April 2022 Plans had been discovered when he and “a lady who looked after my admin stuff” had “rummaged” though some 7,500 files located variously in his double garage 26 and at their house. As noted above, Mr Waring also explained he is presently in his seventies and is experiencing health issues which may be affecting his 27 capacity.

87. The Original Tribunal appears to have found that Mr Mitchell supplied a copy of the April 2022 Plans to Mr Waring at or around the time of their meeting on

24 See the ACAT Act at sections 7, 23 and 26 25 Transcript of hearing dated 10 October 2025, pages 39 to 41 26 Transcript of hearing dated 10 October 2026, pages 62 to 64 27 Transcript of hearing dated 10 October 2026, pages 96 to 97 27 March 2023. This is precisely the point for which Mr Mitchell contended and tends to support Mr Mitchell’s contention that, instead of re-approving the proposed straw-bale house plans on 5 May 2023, Mr Waring had the opportunity to approve the revised plans relating to the prefabricated house.

88. I am not satisfied that it was unfair for the Original Tribunal to have regard to the April 2022 plans produced by Mr Waring during the hearing. Ultimately, this worked in Mr Mitchell’s favour. I deal with the issue of professional competence below.

89. For what it is worth, in my view the same analysis applies in relation to the inspection records only disclosed to Mr Mitchell when Mr Waring emailed them to the tribunal in September 2025 (a proposition not disputed by Mr Waring). The Original Tribunal found that Mr Waring “visited the site at least four times between June and October and completed three inspection records and checked on the prefabricated panels and ground floor and first floor framing; however, did not sent or give these records to anyone”. Later, when the Original Tribunal decided that the appropriate outcome was that Mr Waring should repay 40% of the fee he had received from Mr Mitchell, the Tribunal took into account that Mr Waring “did not provide the inspection records to the owner which may have 28 assisted the owner”.

90. It appears therefore that the Original Tribunal took into account Mr Waring’s late production of the inspection records as a factor which contributed to its decision to order Mr Waring to repay 40% of his fee.

91. Mr Mitchell has not articulated what other outcome should have been reached by the Tribunal by reason of the late disclosure of the inspection records. In my view, notwithstanding the unusual circumstances in which they were produced, it would have been erroneous for the Original Tribunal to refuse to have regard to the inspection records altogether, among other things because they were supported by what on their face were authentic contemporaneous entries in Mr Waring’s diary.

28 Transcript of hearing, 17 October 2026, page 5, lines 11 to 12

92. It may be that the real point which Mr Mitchell seeks to make in relation to the way in which Mr Waring produced both the April 2022 Revised Plans and the inspection records is evidence of his professional incompetence. I accept there is some merit in a submission of this kind.

Ground 3 — incorrect analysis/insufficient weight to evidence of lack of professional competence of Mr Waring

93. In my view, error is established in respect of Mr Mitchell’s assertions that the Original Tribunal gave insufficient weight to the evidence of Mr Waring’s lack of professional competence. I explain my reasons as follows.

94. As I have noted above, the Original Tribunal approached the issue of the damages sought by Mr Mitchell without reference to any particular cause of action. This is not entirely surprising, because Mr Mitchell took the same approach.

95. Ultimately, however, Mr Mitchell’s Application was a claim in contract. As I have noted, he made the following main assertions about the basis on which he submitted Mr Waring should be found liable: (a) Mr Waring failed to provide the certification services for which he was engaged by Mr Mitchell; and/or (b) to the extent that Mr Waring did any certification work, the steps he took were either completed incorrectly or did not assist in progressing the Building Project towards certification; and (c) as a result, Mr Mitchell had suffered losses totalling $33,473 (and claimed damages at the capped amount of $25,000).

96. Mr Mitchell’s claim against Mr Waring was, in effect, a claim based on an alleged breach by Mr Waring of an implied contractual obligation to exercise due care and skill in connection with the provision of certification services. The implication of such a duty in a contract for certification services is 29 uncontroversial. It follows that, in order to succeed, Mr Mitchell had to 30 establish: (a) a contract; (b) a breach of the contractual obligation to exercise due care and skill; (c) loss or damage, including quantification of each item of loss claimed; (d) causation; (e) reasonable foreseeability of the claimed loss(es); and (f) mitigation of loss (if relevant).

97. In this particular case, in my view, the effect of the contributory negligence provisions in Part 7.3 of the Civil Law (Wrongs) Act 2002 (CL(W) Act) also needed to be taken into account by the Original Tribunal. I explain my views in relation to the contributory negligence issue below.

98. The Original Tribunal did not analyse Mr Mitchell’s claim by reference to the above elements, which in my view constituted legal error. The error is significant because, in my view, when the required analysis is undertaken, it leads to a conclusion that Mr Waring fundamentally breached his contractual duty owed to Mr Mitchell to exercise due care and skill, which in turn affects the quantum of damages payable by Mr Waring to Mr Mitchell.

How Mr Waring breached his contractual duty

99. There is no question in the present case that Mr Waring entered into a contract to provide certification services to Mr Mitchell. Likewise, as I have set out above, it is uncontroversial that that contract contained an implied obligation to exercise due care and skill. 31

100. In Hyblewski v Bellerive Homes Pty Ltd (Hyblewski), Mossop J held that the content of a certifier’s contractual duty to exercise reasonable care and skill is to

29 It is uncontroversial that an obligation to exercise reasonable care and skill is to be implied by necessary implication in circumstances such as the present — see for example Hyblewski v Bellerive Homes Pty Ltd [2019] ACTSC 44 at [62]-[71] per Mossop J 30 See for example Ryan v Cheqrouni (No 2) [2024] ACTSC 230 31 [2019] ACTSC 44 at [62]-[71] be determined having regard to the various statutory obligations of a certifier under the Building Act 2004. Centrally, those obligations include: (a) prior to the commencement of building work, reviewing and (if appropriate) approving plans setting out the building work proposed to be undertaken; (b) carrying out inspections of building work at relevant stages to ensure that it complies with section 42 of the Building Act 2004 by being both in accordance with the approved plans and carried out in a proper and skilful way; and (c) if not satisfied that building work complies with section 42, declining to issue an inspection certificate and giving directions to the builder that are reasonable and appropriate for achieving compliance with the requirements 32 of section 42.

101. As observed by Mossop J in Hyblewski, the requirements of section 42, and the role of certifiers in monitoring compliance with that provision, are important in 33 protecting public confidence in the building process.

102. Once the implied contractual duty of a certifier to exercise due care and skill is understood in this way, it is in my view beyond argument that the following actions of Mr Waring, in combination, involved a breach of his duty to exercise due care and skill: (a) on 5 May 2023, Mr Waring formally approved a set of plans in respect of the Building Project which he knew had been superseded and were in fact out of date by three years (i.e. the plans from 2020 for the straw bale house); and (b) on 22 June 2023 and 7 July 2023, Mr Waring carried out inspections at the Site and, I am satisfied, verbally approved the continuation of building work notwithstanding that he knew the building work being undertaken was

32 Ibid at [64] 33 Ibid at [65] for the construction of a prefabricated building and notwithstanding he also knew that there were no approved plans for any such construction; and (c) related to the above, on 22 June 2023 and 7 July 2023 Mr Waring completed inspection records purporting to certify that the building work at the Site was “in accordance with approved plans”, and then failed to provide those inspection records either to Mr Mitchell or the ACT Government; and (d) over the ensuing months, up until the lapsing of his licence at the end of October 2023, Mr Waring continued to allow building work for the construction of a prefabricated house at the Site to proceed, notwithstanding that he continued to know that appropriate plans still had not been 34 approved.

103. I accept that there is some evidence that Mr Waring had communicated to Mr Mitchell in March 2023, or attempted to communicate, that he (Mr Waring) proposed to re-approve the straw-bale-house plans from 2020 as a way of assisting Mr Mitchell to avoid paying any further building approval fee. The problems with Mr Waring relying on that evidence, however, are: (a) it is not clear that Mr Mitchell understood, at the time, what Mr Waring was proposing to do; (b) regardless, it must have been clear to Mr Waring by early June 2023 that Mr Mitchell knew and was concerned that the outdated plans had been approved (I accept Mr Mitchell’s evidence that he spoke to Mr Waring to this effect in early June 2023); and (c) regardless, by the time he was carrying out an inspection on 22 June 2023, and in the ensuing months, Mr Waring clearly had an ongoing contractual duty and statutory obligation not to approve nor to permit the carrying out of building work except in accordance with appropriate approved plans.

34 This last proposition obviously involves accepting the evidence, which Mr Waring himself did not dispute, that Mr Waring did not provide his 3 October Inspection Record either to Mr Mitchell or to the ACT Government at the time, and its existence was not known at all to Mr Mitchell until September 2025

104. Of course, as a licenced owner-builder for the Building Project, Mr Mitchell was also subject to a statutory obligation not to carry out nor authorise the carrying out of building work other than in accordance with approved plans. That proposition is relevant to questions of contributory negligence, and potentially causation (discussed further below), but does not diminish the force of the conclusion that Mr Waring was in fundamental breach of his contractual duty to exercise due care and skill. Put another way, and as contended by Mr Mitchell, in my view the Original Tribunal erred by incorrectly analysing and/or giving insufficient weight to the evidence of a lack of professional competence on the part of Mr Waring.

105. That conclusion as to a lack of professional competence on Mr Waring’s part is reinforced by the evidence indicating that Mr Waring “misplaced” for several years both the three inspection records relating to his certification activities regarding the Building Project in 2023, and his copy of the April 2022 Plans.

Ground 4 — incorrect analysis/insufficient weight to evidence of “falsification” of documents

106. On its face, the Form was signed by Mr Mitchell on 15 December 2023 and indicated that Mr John Bates had taken over from Mr Waring as certifier for the Building Project. The Original Tribunal found that the Second Change of Certifier Form was “not completed correctly” with the result that Mr Bates did not take on the role and Mr Mitchell had no certifier between about 35 November 2023 and April 2024. There was no finding one way or the other as to whether Mr Mitchell’s signature on the Form had been falsified. As noted above, the Original Tribunal did not allow any of Mr Mitchell’s claims for consequential losses.

107. In substance, Mr Mitchell contends that the Original Tribunal ought to have found that his signature on the “Change of Certifier” form was “falsified” and that this conclusion ought to have been taken into account by the Original Tribunal when weighing Mr Waring’s evidence and in assessing the financial losses caused to

35 Transcript, 17/10/25, pp 4-5 Mr Mitchell by Mr Waring’s conduct. This was a position which Mr Mitchell 36 articulated before the Original Tribunal.

108. A first point that can be made regarding this issue is that it is difficult to see how Mr Mitchell’s allegations regarding the Second Change of Certifier Form, whether accepted or not, are relevant to his claim for breach of contract against Mr Waring. Mr Mitchell learned in early December 2023 that Mr Waring’s licence as a certifier had been cancelled. It follows that Mr Mitchell must have known from this time that his contract for services with Mr Waring was at an end. If Mr Waring engaged in further conduct at this stage which was damaging to Mr Mitchell, although it may be actionable in some other way, it could not amount to a breach of contract. It may be this factor was influential in leading the Original Tribunal not to make any finding one way or the other as to this issue.

109. Mr Mitchell’s position, however, is that the Original Tribunal ought to have reached a conclusion about the authenticity of the Second Change of Certifier Form because it was fundamental to an assessment of Mr Waring’s credibility. Mr Mitchell is also seeking a full exposition of the circumstances which have led 37 to his current predicament.

110. Given that the parties dedicated considerable time to this issue, and its importance to Mr Mitchell, I am prepared to indicate my views. Adopting the cautious 38 approach espoused by cases such as Briginshaw v Briginshaw, I am nonetheless comfortably satisfied that it was open to the Original Tribunal to have found that the Second Change of Certifier Form was falsified by, or by persons unknown for the benefit of, Mr Waring by the copying and making of the following alterations to the First Change of Certifier Form:

36 See e.g. transcript of the hearing, 10 October 25, page 19, lines 28 to 31 37 On the appeal, in my discretion, I allowed Mr Mitchell’s “side by side” analysis of what the parties agreed was a genuine “Change of Certifier” form signed by Mr Mitchell and his wife Melynda Mitchell on 14 April 2023 and the form dated 15 December 2023 which Mr Mitchell claimed to have been falsified: see Ex A6 in the appeal 38 The decision of the High Court in Briginshaw v Briginshaw (1938) 60 CLR 336 is regularly cited in support of the proposition that where an alleged act, if proved, amounts, for example, to a crime, even though the standard of proof remains the civil standard, in considering whether the allegation is established the tribunal of fact must be conscious of the gravity of the allegation and of the need to be satisfied of the matter by clear and cogent evidence (a) the building approval number issued by the ACT Government in May 2023, namely “B20231634”, was handwritten under the words “Change of Certifier” on page one of the Form; (b) the name of Mr Mitchell’s wife, Melynda Mitchell, on page 1, and Mrs Mitchell’s signature on page 2, were deleted/blotted out; and (c) the details of the new certifier at “Part C” on the second page were changed from Mr Waring (in the First Change of Certifier Form) to Mr Bates (in the second form).

111. The following aspects of the evidence support the above conclusion: (a) The many identical aspects of the handwriting on the two versions of the Change of Certifier form, including the identical slope of the handwriting, the identical location within the text boxes of the handwriting, the identical location of the “$” on page 1, the identical strike through of the letters “DO” in the spelling of “DOUG MITCHELL” at the foot of page 1, and the identical form of signature of Mr Mitchell on each Form. (b) The multiple items of evidence indicating that, early in 2024, Mr Mitchell was unaware that any “Change of Certifier” form had been filled out (Mr Mitchell adduced evidence showing that he repeatedly contacted Mr Waring in 2024, asking him to complete the “paperwork” required to give effect to the change of certifier to Mr Bates). (c) The fact that, although Mr Waring was never formally cross-examined, at no point during the Original Hearing nor the Appeal Hearing did Mr Waring deny having fabricated the Change of Certifier form. Indeed Mr Waring conceded that he knew that there had been “wiping out” in 39 relation to the signatures on the form (although not by him personally) and at a different point stated “I really wanted to help and the decisions I 40 made were probably very wrong in the legal sense”.

112. I accept Mr Mitchell’s contention that the above finding is relevant to an assessment of Mr Waring’s credibility, and that it supports — though in my view

39 Transcript of the appeal hearing, 10 April 2026, page 101, line 31 40 Transcript of the appeal hearing, 10 April 2026, page 102, lines 3 to 4 is not necessary to — the finding that Mr Waring fundamentally breached his contractual duties to Mr Mitchell.

113. I deal with the issue of potential additional financial loss caused to Mr Mitchell by the falsification of the Second Change of Certifier Form below.

Ground 5 — incorrect analysis/failure to accept evidence of additional costs incurred by Mr Waring

114. In essence, this alleged error is an assertion by Mr Mitchell that the Original Tribunal ought to have accepted his various claims of alleged loss.

115. As noted above, in order to be successful in this context, once contractual breach was established, it was necessary for Mr Mitchell to demonstrate, in respect of each item of asserted loss, that the loss is quantifiable, was caused by the breach, and was reasonably foreseeable.

116. It is also necessary to take into account, to the extent relevant, issues of mitigation of loss and potential contributory negligence by Mr Mitchell. Contributory negligence is relevant because: (a) Mr Mitchell’s claim was, in effect, a claim based on an alleged breach by Mr Waring of a contractual obligation to exercise due care and skill in connection with the provision of certification services; (b) Mr Mitchell’s claim was, therefore, in respect of a “wrong” within the meaning of Part 7.3 of the CL(W) Act, namely, an act or omission “that amounts to a breach of a contractual duty of care that is concurrent and 41 coextensive with a duty of care in tort”; and (c) it follows that, if Mr Mitchell suffered loss partly because of his own failure to take reasonable care, the damages recoverable by Mr Mitchell in respect of Mr Waring’s breach of contract are to be reduced to the extent that the 42 court considers just and equitable.

41 CL(W) Act, s 101 42 CL(W) Act, s 102 Certification fee ($3,300)

117. The Original Tribunal ordered that Mr Waring repay 40% of the certification fee paid to him by Mr Mitchell, being a sum of $1,320. Mr Mitchell contends, as part of the appeal, that Mr Waring should have been ordered to repay the full amount of $3,300.

118. I agree with Mr Mitchell. In my view, the Original Tribunal ought to have concluded that the certification services provided by Mr Waring were of no commercial value at all. Not only did Mr Waring never approve a current set of plans for the proposed prefabricated house, he approved a set of plans which had been superseded but then let building work continue for a further five months, including at a time when he knew his certification licence was about to be cancelled. Ultimately, Mr Waring’s involvement did not just fail to advance the Building Project; it set the Project back by resulting in the need for a retrospective and more expensive “as built” certification process.

119. In my view, the loss of the full value of the amount paid (in advance) by Mr Mitchell was a foreseeable result of Mr Waring’s breach. Mr Waring knew that work on a prefabricated house was being carried out without approved plans. That created a risk for Mr Mitchell, the level of which increased the longer that the work continued. Specifically, if Mr Waring became unavailable for any reason, the absence of approved plans would mean it was impossible for another certifier to step in to take over the certification work. The status quo prevailed not for days or weeks, but months.

120. As to mitigation of loss, I am satisfied on the evidence that, even though Mr Waring may have signalled in his email to Mr Mitchell of 27 March 2023 that he intended, at least initially, to re-approve plans for the straw-built house rather than the prefabricated house, Mr Mitchell did not comprehend this until after he had paid Mr Waring’s fees in full. Thereafter, I am satisfied, Mr Mitchell raised the issue of the incorrect plans having been approved, but Mr Waring assured him it could be all be dealt with “later”. This approach might have involved a breach of Mr Mitchell’s statutory responsibilities as a licensed owner builder under the Building Act 2004, but I am not persuaded that it involved an unreasonable failure to mitigate the losses caused by Mr Waring’s breach of contract. On this issue, Mr Waring bears the onus of proof. Mr Waring has not established on the balance of probabilities that, had Mr Mitchell taken additional reasonable steps, the complete loss of the value of the money already paid by him to Mr Waring would not have eventuated.

121. The same analysis applies in relation to the issue of contributory negligence. At the point in time at which Mr Mitchell paid the $3,300 to Mr Waring (27 March 2023), he had not engaged in any act which could constitute contributory negligence. The culpable omissions of Mr Mitchell, if any, only occurred later after Mr Mitchell learned that Mr Waring had approved the superseded straw-bale-house plans.

122. It follows that, in my view, the Original Tribunal ought to have ordered Mr Waring to repay the full amount of the certification fees ($3,300) rather than just 40% of the value of those fees.

Costs of obtaining engineering design certificate and updated version ($2,310)

123. The available evidence indicates that Mr Mitchell paid $1,980 towards the cost of an engineer’s certificate in about June 2023, and then a further $330 to have that certificate updated in October 2023. There was then a further $550 incurred as payment for a “final engineering certificate” in January 2025. Mr Mitchell contends that he “might not” have had to incur these expenses had Mr Waring been more diligent in the discharge of his duties as a certifier at an early stage.

124. The available evidence does not support a conclusion that the incurring of the abovementioned engineering costs by Mr Mitchell was a loss caused by a breach of contract by Mr Waring.

125. First, the incurring of the first of the abovementioned engineering costs was not related to the issue of Mr Waring having approved the “wrong” plans. On the evidence, Mr Mitchell commenced the process of obtaining the engineering certificate on the assumption that such a certificate would be needed for the purpose of the prefabricated house, before he knew that Mr Waring had approved the plans related to the straw bale house. Thus, Mr Waring’s breach of contract did not cause Mr Mitchell to incur the engineering expenses.

126. Secondly, on the evidence, the unusual nature of the structure being built by Mr Mitchell — an imported, prefabricated house — means, in my view, that it is likely that the incurring of the engineering costs would have been necessary in any event. The available evidence demonstrates that the contractor engaged by Mr Mitchell, Mr Spencer, was concerned about aspects of the structural soundness of the building being erected and sought engineering input. Section 47 of the Building Act 2004 provides that the owner of a parcel of land “must, if required by a certifier” give the certifier an engineering certificate dealing with the structural sufficiency, soundness and stability of the building as erected. In my view it is likely that, given the unusual nature of the structure being built on this occasion, and the concerns expressed at an early stage by Mr Spencer, a competent certifier would have issued a requirement under section 47.

127. Mr Mitchell has not established, on the balance of probabilities, that the engineering costs which he has identified would not have been incurred regardless of any contractual breach of Mr Waring. The Original Tribunal was therefore correct to find that this head of damages had not been established.

Fees “paid to Kevin Guo” ($7,000)

128. Kelvin Guo was the principal of a construction management firm, “Trone Projects”, engaged by Mr Mitchell in late June 2023 to oversee the progress of the building project. Mr Mitchell contended that he paid Mr Guo at an hourly rate to carry out additional work on the building project, necessitated by Mr Waring’s inattention to the certification process, with the relevant amounts coming to “about” $7,000.

129. Trone Projects was engaged by Mr Mitchell immediately prior to him travelling overseas for several months. Although there is some evidence of inattention on the part of Mr Waring by this stage, it appears equally plausible that the reason that Mr Mitchell engaged Trone Projects was that he knew he would be unable himself to discharge his responsibility of supervising the building work being 43 undertaken at the Site.

130. As noted by the Original Tribunal, Mr Mitchell did not provide a Scott schedule in conjunction with his claim. Although a copy of the contract between Mr Mitchell and Trone Projects was provided, no copies of invoices from Trone Projects nor records of hours worked were tendered. Moreover, the relevant amounts would have been payable to Trone Projects, not to Mr Guo.

131. Mr Mitchell failed to put the Original Tribunal in a position where it could have been satisfied that Mr Guo, as opposed to Trone Projects, did a quantifiable amount of additional work necessitated by a proven breach of contract on the part of Mr Waring. The Original Tribunal was right to find that this alleged loss of Mr Mitchell was not substantiated.

Rates paid to ACT government ($4,261)

132. Mr Mitchell’s claim in respect of rates is that “the lack of communication from [Mr Waring] both prior to and after the lapse of his license [sic], has resulted in [Mr Mitchell] paying rates for the Building Project in excess of what he otherwise 44 would have paid”. The claim relates to an amount of $4,261 paid by way of rates in respect of the Site for the period October 2024 to September 2025. Mr Mitchell’s suggestion seems to be that, had Mr Waring not (incorrectly) maintained that Mr Bates had taken over from him as certifier, Mr Mitchell would have been able, sooner, to be issued with a “stop work” notice in respect of the building work at the Aranda site, something which apparently leads or can lead to an exemption from rates liability.

133. The problem for Mr Mitchell with this claim is that there is no suggestion that, at any stage, he intended to cease being owner of the Site. Had Mr Waring not breached his contractual duty to exercise due care and skill, presumably the Building Project would have been finished on time and without the need for any

43 Section 42(1)(f)(i) provides that building work required to be done only by a licensed builder must be carried out by or under the supervision of the builder mentioned in the building commencement notice 44 See Mr Mitchell’s written submissions filed on 15 September 2025 (Ex 2 in the appeal) at [31] “Stop Work” notice at all. In this scenario, presumably, Mr Mitchell would still as owner have incurred a liability to pay rates in respect of the Site.

134. The Original Tribunal was correct to find that Mr Mitchell failed to establish any compensable loss in respect of this head of damages.

Insurance as owner builder ($4,650)

135. Mr Mitchell’s claim in respect of insurance is that Mr Waring’s conduct delayed the completion of the Building Project, thereby requiring Mr Mitchell to maintain a policy in respect of his owner-builder activities for a longer period. In support of this claim, Mr Mitchell tendered an invoice dated 9 August 2023 requiring him to pay a sum of $4,650 for coverage during the period 12 August 2023 to 12 June 2024. No other invoices were provided, notwithstanding the hearing took place in October 2025.

136. It is plausible that Mr Waring’s failure to exercise due care and skill in his role as certifier may have been a material cause of the type of loss asserted by Mr Mitchell, but the one invoice which Mr Mitchell has produced relates to a period (August 2023 to June 2024) where it appears likely that, at least in part, he would have been required to have insurance in any event — the evidence before the Tribunal was to the effect that, on the assumption that Mr Bates had taken over the role of certification from Mr Waring, the Building Project was approaching completion in February 2024.

137. Mr Mitchell could presumably have produced additional invoices relating to later periods insurance, if any further expenses of this type were incurred. For reasons which are not clear, he failed or declined to do so. In addition, Mr Mitchell did not adduce any evidence of how long completion of the Building Project would have taken if the required certification duties had been performed competently.

138. Courts and tribunal are entitled to take a pragmatic approach to questions of the quantification of loss. Where there has been an actual loss of some sort, the common law will not permit difficulties of estimating that loss to defeat a claim 45 for damages.

139. In the present case, however, the evidence adduced by Mr Mitchell falls short of establishing that an actual loss of the kind alleged occurred. More than mere assertion is required. The failure to adduce additional invoices was unexplained. The Original Tribunal was right to find this alleged loss had not been established.

Fees paid to ACT Certification Services ($1,452)

140. On 22 January 2025, Mr Mitchell paid $1,452 to an entity called ACT Certification Services Pty Ltd to carry out an assessment of the Site to determine what specific steps were required to progress the Building Project towards issue of a Certificate of Occupancy. On the face of it, the incurring of this expense was directly linked to the failure by Mr Waring to discharge his duties as certifier competently, which in turn brought about the necessity for an “as constructed” certification process. This was a foreseeable form of loss arising from Mr Waring’s breach.

141. On the other hand, principles of mitigation and/or contributory negligence are relevant in relation to this item of loss. As I have already noted, and as the Original Tribunal found, as a licensed owner-builder, Mr Mitchell had an obligation to ensure that only building work consistent with approved plans was carried out at the Site, and (putting the same proposition another way), to ensure that no work inconsistent with approved plans was carried out. From about 1 June 2023 onwards, Mr Mitchell entirely failed to discharge this obligation.

142. In my view, having regard to the legislative scheme created by the provisions of the Building Act 2004, the appropriate allocation of responsibility as between Mr Waring (the certifier) and Mr Mitchell (the licensed owner builder) is 50% each. I would therefore allow half the sum claimed by Mr Mitchell under this head, namely, $726.

45 Fink v Fink (1946) 74 CLR 127 at 143, cited with approval in Ryan v Cheqrouni (No 2) [2024] ACTSC 320 at [31]-[32] “Anticipated” cost of obtaining updated building plans ($10,000)

143. Mr Mitchell’s claim before the Original Tribunal included a component of $10,000 for the “anticipated” cost “of obtaining updated building plans”. It appears that this sum is a cost which has not yet been incurred by Mr Mitchell and represents at best a “ball park” estimate of costs which may be incurred by him at some point in the future in order to obtain “as built” plans necessary for the approval process contemplated by section 69(2B) of the Building Act 2004.

144. Costs of the above kind may ultimately form a compensable form of loss in the present matter. In my view, prima facie, they represent a foreseeable form of loss arising from the nature of the contractual breach committed by Mr Waring, although again a reduction to reflect a failure to mitigate and/or principles of contributory negligence will likely be required. It is not possible at this time, however, to quantify the relevant losses. Much may depend on how events unfold from this point — it will be one thing, for example, if Mr Mitchell is ultimately able to get his Building Project approved, but an entirely different question if that is not the case and he is faced with the possibility of a valueless structure.

145. In either event, it would be improper to allow Mr Mitchell’s claim in respect of this head of “anticipated loss” at this stage. I need not decide whether it will be possible for Mr Mitchell to bring another claim for this type of loss, based on more precise evidence, at some point in the future.

Conclusion

146. Mr Mitchell has succeeded in establishing that the Original Tribunal erred, in that it failed to analyse his claim by reference to the cause of action upon which he relied, namely, breach of contract. The Original Tribunal ought to have found that Mr Waring fundamentally breached an implied contractual duty owed to Mr Mitchell to exercise professional skill and competence in the discharge of his duties as a certifier in relation to the Building Project.

147. Although the quantum of the order to be made in the appellant’s favour is not at this stage significantly greater, it is possible that Mr Mitchell may be able to bring a further claim at some later stage.

148. The order of the Original Tribunal should be set aside and substituted with an order requiring Mr Waring to pay the appellant $4,026.00 within 28 days.

……………………………….. Presidential Member M Hassall

Date of hearing: 10 April 2026 Applicant: In Person Respondent: In Person