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Kasto v Mosman Municipal Council [2025] NSWLEC 1460 | Case summary | Zoe

NSWNSWLEC

Kasto v Mosman Municipal Council

[2025] NSWLEC 1460

Land and Environment Court (NSW)|2025-06-27|Before: Horton C

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General information, not legal advice.

At a glance

Source facts

Court

Land and Environment Court (NSW)

Decision date

2025-06-27

Before

Horton C

Catchwords

DEVELOPMENT APPLICATION: dwelling house development in C4 Environmental
Living zone — conciliation conference — agreement
between parties
— orders

Source

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Catchwords

DEVELOPMENT APPLICATION: dwelling house development in C4 EnvironmentalLiving zone — conciliation conference — agreementbetween parties— orders

Judgment

Source: NSW Caselaw (www.caselaw.nsw.gov.au). Converted to plain text by ZoeLaw. Not the official version.

Medium Neutral Citation: Kasto v Mosman Municipal Council [2025] NSWLEC 1460

Hearing dates: Conciliation conference on 18-19 June 2025: final submissions 23 June 2025

Date of orders: 27 June 2025

Decision date: 27 June 2025

Jurisdiction: Class 1

Before: Horton C

Decision: The Court orders that:
(1) The appeal is upheld.
(2) Development Application No. 008.2024.205.001 for demolition, new dwelling house and swimming pool at Lot 2 in DP 556160, known as 10 Illawarra Street, Mosman is determined by the grant of development consent subject to the conditions contained at Annexure A.

Catchwords: DEVELOPMENT APPLICATION: dwelling house development in C4 Environmental Living zone — conciliation conference — agreement between parties — orders

Legislation Cited: Environmental Planning and Assessment Act 1979, ss 1.3, 4.16, 8.7
Land and Environment Court Act 1979, ss 34, 34AA
Environmental Planning and Assessment Regulation 2021, s 38
Mosman Local Environmental Plan 2012, cll 4.3, 4.3A, 4.4, 4.6, 5.10, 6.1, 6.4, 6.6, 6.7
State Environmental Planning Policy (Biodiversity and Conservation) 2021, Ch 2, s 2.6, Ch 6, ss 6.6, 6.7, 6.8, 6.9 State Environmental Planning Policy (Resilience and Hazards) 2021, s 4.6 State Environmental Planning Policy (Sustainable Buildings) 2022, s 2.1

COMMISSIONER: Development for the purpose of a dwelling house is proposed on land located on the northern side of Illawarra Street, perched above Sirius Cove in Mosman.
To this end, development application 8.2024.205.1 was lodged by the applicant, Nadir Kasto (Kasto) in these proceedings with Mosman Council on 2 October 2024, seeking consent for demolition of the existing structures on the site, and the construction of a new dwelling house and swimming pool.
The DA was publicly notified to surrounding residents for a period of 14 days from 22 October 2024 to 5 November 2024 in accordance with the Mosman Community Participation Plan.
As the DA was not otherwise determined, Kasto appealed the deemed refusal of the DA by the Council on 5 December 2024 under s 8.7 of the Environmental Planning and Assessment Act 1979 (EPA Act).
The appeal was listed for mandatory conciliation on 18 June 2025, in accordance with the provisions of s 34AA of the Land and Environment Court Act 1979 (LEC Act).
The matter commenced with an onsite view at which the Court, in the company of the parties and their experts, heard oral submissions from the owners or representatives of the following adjoining properties:
6 Illawarra Street, which is located to the east of the subject site.
10 Illawarra Street, which is located to the north of the site, and accessed via an earthen path from Illawarra Street, with vehicular access from Moran Street to the north.
12 Illawarra Street, which is located to the west of the subject site, elevated due to the rising topography.
The Court was also taken into the property at 14 Illawarra Street, to stand on a south-facing deck to appreciate the view currently enjoyed from this site.
Following the onsite view, I presided at the conciliation conference that convened at Court. During the conciliation, the parties agreed to certain amendments that would resolve the issues in dispute, subject to a short adjournment to prepare amended plans and other documents.
I granted the adjournment and, on the second day of proceedings, and on the basis of the amended plans and agreed conditions of consent, the parties reached agreement as to the terms of a decision in the proceedings that was acceptable to the parties. To this end, the Council approved the amending of the application by the Applicant, in accordance with s 38 of Environmental Planning and Assessment Regulation 2021 (EPA Regulation).
A signed agreement prepared in accordance with s 34(10) of the LEC Act was submitted to the Court on 19 June 2025, and a corrected and complete agreement was subsequently submitted on 23 June 2025.
The parties ask me to approve their decision as set out in the s34 agreement before the Court. In general terms, the agreement grants development consent, subject to the amended plans prepared by the Applicant, and noting that the final detail of the works and plans are specified in the agreed conditions of development consent annexed to this decision at Annexure A.
Under s 34(3) of the LEC Act, I must dispose of the proceedings in accordance with the parties’ decision if the parties’ decision is a decision that the Court could have made in the proper exercise of its functions.
The parties prepared a jurisdictional statement to assist the Court in understanding how the requirements of the relevant environmental planning instruments have been satisfied in order to allow the Court to make the agreed orders at [53].
I formed an opinion of satisfaction that each of the pre-jurisdictional requirements identified by the parties have been met for the reasons that follow.
The site is located within an area designated by the Mosman Local Environmental Plan 2012 (MLEP) as C4 Environmental Living, in which dwelling house development is permitted with consent, where consistent with the following objectives for development in the C4 zone:

The Written Requests assert the proposal shares both public and private views, consistent with objective cl 4.3(1)(a)(i) and cl 4.3A(1A)(a), supported by a Visual Impact Assessment prepared by Urbaine dated 18 June 2025 that shows views to Sirius Cove and Sydney Harbour beyond will be unaffected for the surrounding dwellings, except for a minor obscuring of the western land water interface when viewed from a certain location at 14 Illawarra Street.
In respect of objective cl 4.3(1)(a)(ii), the Written Requests assert that the proposed dwelling is consistent, and in keeping with, existing surrounding development with which it is also compatible. The existing character of the area is one of multi-storey dwellings stepping up along the slope of Illawarra Street, in varying styles. When viewed from Sydney Harbour, the exceedance will not be perceived following amendments to the extent of the exceedance, and in the materials and finishes.
In respect of objective cl 4.3(1)(a)(iii) and cl 4.3(1A)(c), the Written Requests identify the predominant character of the surrounding area to be two and three-storey dwellings, with larger dwellings at four-storeys also depicted.
The site is located within what is known as the Sirius Slopes Townscape, according to Part 7.4(2) of the Mosman Residential Development Control plan (MRDCP). The proposal’s flat roof form is consistent with roof forms in the area, and with the planning controls for the Sirius Slopes Townscape in Part 7 of the MRDCP that regards flat roofs as capable of being acceptable when well-designed to retain views from neighbouring properties.
Finally, the Written Requests addresses objective cl 4.3(1)(a)(iv) and cl 4.3A(1A)(b), by identifying the side setbacks, compliant floor space ratio, stepped form and articulation of the side walls as elements that minimise the adverse effect of bulk and scale, as well as the deep setback from the front boundary to Illawarra Street.
I accept the proposal, as amended, is consistent with the objectives of the height standard and I am satisfied that compliance with the numerical standard is unreasonable or unnecessary, pursuant to s 4.6(3)(a) of the MLEP.
Next, the Written Requests advance environmental planning grounds the parties agree are sufficient to justify the contravention, summarised as follows:
The proposal is consistent with the objectives of the development standard, and achieves the objects of the EPA Act at s 1.3, including to promote good design and amenity in the built environment.
The exceedances are setback from the public domain and so are unlikely to be viewed from Illawarra Street or Sirius Cove.
The exceedance arises, in part, due to the steep slope of the topography that is otherwise minimised by the stepping of the built form, and is in part due to prior excavation of the site that serves to distort the calculation of height.
The gross floor area of the uppermost floor is minimised when compared with the area of floors below, and due to the geometry of the lot, the location of the uppermost floor is generously set back from adjoining properties.
No significant or adverse impacts arise as a consequence of the exceedance.
I am satisfied that the environmental planning grounds are sufficient to justify the contravention of the height standard at cl 4.3, and the additional provisions in respect of height at cl 4.3A of the MLEP.
As I am satisfied Kasto has demonstrated those matters at cl 4.6(3) of the MLEP, I am also of the view that there is no reason the Written Requests should not be upheld.

The relevant floor space ratio permitted on the site at cl 4.4 of the MLEP is 0.5:1 or a maximum gross floor area of 300.5m2, with which the amended proposal now complies.
The proposed development is in the vicinity of two items of local heritage significance, namely the vegetated reserve in Illawarra Street, and 14 Illawarra Street. On the basis of the reduced area in the uppermost terrace, and its substitution with a green roof, I accept the proposal is acceptable when viewed in context with the heritage items in the vicinity of the site, in terms set out in cl 5.10 of the MLEP.
According to the Acid Sulfate Soils Map at cl 6.1(2) of the MLEP, the site is not affected by Acid Sulfate Soils.
The site is identified within the Scenic Protection Area by the relevant map at cl 6.4(2) of the MLEP. On the basis of the setback of the uppermost level, the low native landscape planting to the green roof in the location of the uppermost terrace originally proposed, and the agreement on a muted materials and finishes palette, I am satisfied the built form as amended has the effect of minimising the visual impact of the development to and from Sydney Harbour, and the development will maintain the existing natural landscape and landform, including plantings in the front setback.
As the site has an area of 601.8m2, cl 6.6(3)(a)(iv) of the MLEP requires 35% of the site area to be landscaped area. The parties agree the proposed development provides a complying landscaped area.
The proposed development includes additional excavation beyond that currently on the site. A Geotechnical Investigation Report prepared by AE Geotechnical dated 22 July 2024 records the location and findings of 3 boreholes drilled on site and additionally recommends:
Dilapidation survey of neighbouring/adjoining infrastructure
Inspection for confirmation of bearing capacity prior to the placement of footings/piers.
Inspection prior to any vertical cut/rock excavation, and
Inspection prior to installation of any shoring piles.
I have considered those matters at cl 6.7(3) of the MLEP and conclude the proposed excavation is reasonable when the steep topography, extent of prior excavation and nature of development in the area is considered. In particular I note the Stormwater Plans prepared by AE Consulting depict the collection of stormwater into a 4,000L rainwater tank and onsite detention tank (OSD), prior to the release into the Council infrastructure via water quality devices in two new stormwater silt arrestor pits located in the front setback. As such the proposal would appear to improve the existing drainage pattern on the site, in the south eastern corner adjoining Nos 6 and 8 Illawarra Street.

Chapter 2 of the State Environmental Planning Policy (Biodiversity and Conservation) 2021 (Biodiversity SEPP) applies to the site, and s 2.6 allows for the removal of vegetation with consent. However, no trees are proposed for removal on the site, or on adjoining sites.
The site is located within the Sydney Harbour Catchment as identified by the Sydney Harbour Catchment Map. That said, the parties agree the site is not within the Foreshores and Waterways Area, is not a strategic foreshore site, a heritage item or land within a wetlands protection area.
Section 6.6 of the Biodiversity SEPP precludes the grant of consent unless the Respondent council, or the Court on appeal, is satisfied that the proposed development ensures that, firstly, the effect on the quality of water entering a natural waterbody will be as close as possible to neutral or beneficial, and secondly, that the impact on water flow in a natural waterbody will be minimised.
The Stormwater Plans cited at [38] depict rainwater tanks and onsite detention (OSD) tanks fitted with water quality devices nominated to include Ocean Guard and filter screens. The Stormwater Plans also provide DRAINS modelling results to indicate a reduction in outward flow from the OSD tank proposed on the site, which satisfies me that the effect on the quality of water entering a natural waterbody will be as close as possible to a neutral or beneficial impact, in accordance with s 6.6(2)(a), and that water flow in or to a natural waterbody will be minimised, pursuant to s 6.6(2)(b) of the Biodiversity SEPP.
For similar reasons I have also considered those matters at s 6.7(1) of the Biodiversity SEPP and am satisfied there will be no direct, indirect or cumulative impact on terrestrial, aquatic or migratory animals or vegetation, and result in no adverse impact on aquatic reserves, or in terms of erosion.
I note that the site is not identified as flood liable land to which s 6.8 of the SEPP is directed and so does not apply.
Neither will the proposed development have an impact on recreational land uses or access to public land, in terms set out in s 6.9 of the Biodiversity SEPP.