Land and Environment Court of New South Wales CITATION : 577 New South Head Road Pty Ltd v Woollahra Municipal Council [2004] NSWLEC 526 APPLICANT 577 New South Head Road Pty Ltd PARTIES : RESPONDENT Woollahra Municipal Council FILE NUMBER(S) : 10967 of 2003 CORAM: Nott C KEY ISSUES: Development Consent :- application to modify a SEPP 5 development - whether substantially the same development - amenity of owners of a heritage item at 1 Rose Bay Avenue - modification involving increased excavation on a hillside closer to the boundary of 1 Rose Avenue LEGISLATION CITED: CASES CITED: Pegasus Construct and Design v Woollahra Municipal Council No. 10150 of 1997 (unreported, 6 October 1998); Moto Projects (No. 2) Pty Limited v North Sydney Council (1999) 106 LGERA 298 DATES OF HEARING: 15 & 16/03/2004, (mention 03/08/2004), 17/09/2004 DATE OF JUDGMENT: 09/21/2004 APPLICANT Mr D Wilson, barrister SOLICITORS Acuiti Legal LEGAL REPRESENTATIVES: RESPONDENT Mr M Connell, solicitor SOLICITORS Mitchell Sillar JUDGMENT: IN THE LAND AND ENVIRONMENT COURT OF NEW SOUTH WALES Nott C 21 September 2004 10967 of 2003: 577 New South Head Road Pty Ltd v Woollahra Municipal Council JUDGMENT 1 COMMISSIONER: This is an appeal under s 96 of the Environmental Planning and Assessment Act 1979 in respect of the council's refusal to modify a development consent granted by the council for 11 self-care units with basement carparking at 577 New South Head Road, Rose Bay (on the corner of Rose Bay Avenue). 2 The development consent is contained in a notice of determination dated 28 January 2003, and the consent was granted pursuant to State Environmental Planning Policy No. 5—Housing for Older People or People with a Disability . The development consent also included approval for the demolition of the existing dwelling house and ancillary structures on the subject site. 3 At the hearing, the main issues were: · whether the proposed modified development is substantially the same as that for which consent was granted; · whether the increased excavation of the subject site and method of retention of the excavated land might adversely impact upon the stability of the adjoining property at 1 Rose Bay Avenue; and · the amenity of the adjoining residents at 1 Rose Bay Avenue. 4 It is necessary to first examine in some detail the conditions of the consent dated 28 January 2003. The conditions included the following: 1. New development The development must be carried out in accordance with plans numbered DA05-DA08; DAIO, DA12-DA16, dated April 2002, drawn by mgt architects, including landscape plans numbered DA/L0I Rev A dated January 2003 and DA/L02, dated September 2002, drawn by mgt architects, all of which carry a Council stamp " Approved DA Plans " and the signature of a Council officer, except where amended by the following conditions. … 62. Dilapidation reports A practising structural engineer must prepare a detailed dilapidation report on the current structural condition of the existing structures at the following locations: · Concrete path and steps in Cranbrook Lane · Concrete footpath adjoining the site in Rose Bay A venue · 1 Rose Bay A venue, Rose Bay · Council's reserve between Rose Bay Avenue and New South Head Road The Report must be completed and submitted to Council prior to the commencement of any demolition, excavation or construction works. A second dilapidation report, recording structural conditions of all structures originally assessed prior to the commencement of works, must be carried out at the completion of the works and be submitted to Council. 63. Support for Council roads, footpaths, drainage reserves, etc Council property adjoining the construction site must be fully supported at all times during all excavation, demolition and building construction works. Details of shoring, propping and anchoring of works adjoining Council property, prepared by a qualified –Structural Engineer or Geotechnical Engineer, must be submitted for the approval of Council's Development Engineer, or certified as structurally adequate by the accredited certifier; before the commencement of any works. Backfilling of excavations adjoining Council property, or any void remaining at completion of construction between the building and Council property, must be fully compacted prior to release of the Damage Security Deposit. 64. Earth/rock anchors The use of permanent rock anchors under Council land is not permitted. Temporary rock anchors may be permitted, where alternative methods of stabilisation would not be practicable or viable, and where there would be benefits in terms of reduced community impact due to a shorter construction period, reduced disruption to pedestrian and vehicular traffic on adjacent public roads, and a safer working environment. If temporary rock anchors under Council land are proposed, a separate application, including payment of fees, must be made to Council under Section 138 of the Roads Act 1993 . Approval may be granted subject to conditions of consent. Four weeks should be allowed for assessment. 65. Compliance with recommendations of the geotechnical report The development works are to be undertaken in accordance with the recommendations of the Report on Geotechnical Investigation – 577 New South Head Road, Double Bay, prepared by Douglas Partners, project 30226, dated February 2002.. 66. Compliance with the implementation plan and geotechnical monitoring program The implementation plan and geotechnical monitoring for the development must be in accordance with the recommendations of the "Report on Geotechnical Investigation -577 New South Head Road, Double Bay" prepared by Douglas Partners, project 30226, dated February 2002. Monitoring and inspection at the hold points recommended in the Report on Geotechnical Investigation – 577 New South Head Road, Double Bay, prepared by Douglas Partners, project 30226, dated February 2002, must be conducted and certified by a qualified geotechnical/hydrogeological engineer. Copies of the inspection and monitoring reports must be supplied [to] the Accredited Certifier within 7 days of the inspection. Any non-conformance must be immediately conveyed to the Accredited Certifier with a Corrective Action Plan. 67. Vibration during Construction Vibration during construction can adversely affect surrounding property and infrastructure. Construction techniques, such as the installation of sheet piles, require the use of vibratory or impact hammers and produce ground vibrations. Prior to the issue of the Construction Certificate, the applicant must submit to the Accredited Certifier details of the proposed Vibration Monitoring Program to ensure that vibration created by the method of construction does not adversely impact on the existing building, surrounding property and infrastructure. A qualified and practising geotechnical and/or hydrogeological engineer must prepare the Vibration Monitoring Program and undertake all associated investigations. Details to be included in Vibration Monitoring Program to include: a) pre-set acceptable limits for the variation of: i) settlement ii) deflection or movement of retaining mechanisms such as shoring and bracing and iii) vibration in accordance with AS 2187.2 1993 Appendix J, including acceptable velocity of vibration. b) the location and type of monitoring systems to be used c) recommended hold points to allow for inspection and certification by a geotechnical engineer and d) a contingency plan should the pre-set acceptable limits be exceeded. 68. Certification of Vibration Monitoring A record of inspections and monitoring of vibration in accordance with the Vibration Monitoring Program must be submitted in a report form to the Accredited Certifier, prior to release of the Certificate of Occupancy. A qualified and practising engineer must prepare certification. … 86. Compliance with Building Code of Australia (a) All building work must be carried out in accordance with the provisions of the Building Code of Australia . (Refer to Advising 19) … 89. Excavations and backfilling (a) All excavations and backfilling associated with the erection or demolition of a building must be executed safely and in accordance with appropriate professional standards. (b) All excavations associated with the erection or demolition of a building must be properly guarded and protected to prevent them from being dangerous to life or property. 90. Retaining walls and drainage If the soil conditions require it: (a) retaining walls associated with the erection or demolition of a building or other approved methods of preventing 'movement of the soil must be provided; and (b) adequate provision must be made for drainage. 91. Support for neighbouring buildings (a) If an excavation associated with the erection or demolition of a building extends below the level of the base of the footings of a building on an adjoining allotment of land, the person causing the excavation to be made: (i) must preserve and protect the building from damage; and (ii) if necessary, must underpin and support the building in an approved manner; and (iii) must, at least 7 days before excavating below the level of the base of the footings of a building on an adjoining allotment of land, give notice of intention to do so to the owner of the adjoining allotment of land and furnish particulars of the excavation to the owner of the building being erected or demolished. b) The owner of the adjoining allotment of land is not liable for any part of the cost of work carried out for the purposes of this condition, whether carried out on the allotment of land being excavated or on the adjoining allotment of land. (c) In this condition, allotment of land includes a public road and any other public place. 92. Protection of public places (a) If the work involved in the erection or demolition of a building: (i) is likely to cause pedestrian or vehicular traffic on a public place to be obstructed or rendered inconvenient, or (ii) building involves the enclosure of a public place; (iii) a hoarding or fence must be erected between the work site and the public place. (b) If necessary, an awning must be erected, sufficient to prevent any substance from, or in connection with, the work falling into the public place. (c) The work site must be kept lit between sunset and sunrise if it is likely to be hazardous to persons in the public place. (d) Any such hoarding, fence or awning must be removed when the work has been completed. Note : Prior to the erection of any hoarding, fence or the like on any footpath or other property owned or controlled by Council, permission must be sought and obtained from Council and the prescribed rental fee paid. 93. Signs to be erected on building and demolition sites (a) A sign must be erected in a prominent position on any work site on which work involved in the erection or demolition of a building is being carried out: (i) stating that unauthorized entry to the work site is prohibited; and (ii) showing the name of the person in charge of the work site and a telephone number at which that person may be contacted outside working hours. (b) Any such sign must be removed when the work has been completed. (c) This clause does not apply to: (i) building work carried out inside an existing building; or (ii) building work carried out on premises that must be occupied continuously (both during and outside working hours) while the work is being carried out. … 96. Excavation The outer edge of excavation, piling and all sub-surface walls is to be in accordance with the excavation line and dimensions as marked up on drawing numbered DA12, dated April 2002, drawn by mgt architects. 5 It can be seen from condition 1 above that only certain plans in the series of plans were mentioned as being approved. These approved plans were tendered in evidence as exhibit 2 and are the following: DA05 level 2 and level 3 plan, elevation DA06 level 4 and level 5 plan, elevations DA07 level 6 and roof plan, elevations DA08 level 1 carpark plan, level 5 study, sections DA10 materials study/collage DA12 level 1 plan DA13 level 2 plan DA14 level 3 plan DA15 level 4 plan DA16 level 5 plan DA/LO1 rev A landscape plan DA/LO2 landscape sections. 6 There were also other plans that are part of exhibit 2, although they were neither approved nor disapproved, and these plans are: DA01 context plan DA02 site analysis DA03 site setback analysis and site analysis diagrams DA04 view analysis DA09 shadow studies. 7 The architectural plans which accompanied the modification application under s 96 are contained in exhibit A and comprise the following: Amended section 96 05 level 2 and level 3 plan, elevation Amended section 96 06 level 4 and level 5 plan, elevations Amended section 97 07 level 6 and roof plan, elevations Amended section 96 08 level 1 carpark plan, level 5 study, sections Amended section 96 10 materials studies/collage Amended section 96 13 level 2 plan Amended section 96 14 level 3 plan Amended section 96 15 level 4 plan Amended section 96 16 level 5 plan Amended section 96 L01 landscape plan Amended section 96 L02 if landscape sections As indicated by the title of these plans, "Amended section 96…", the s 96 application was amended for the purpose of the hearing of the appeal. This appeal is concerned now only with the amended s 96 plans mentioned above. For convenience, I will refer to the proposed modified development shown in these amended s 96 plans as simply "s 96 plan 05", "s 96 plan 06" etc. 8 The engineers, Messrs Green and Mostyn, were critical of the retaining walls shown on some of the s 96 architectural plans in exhibit A, which they considered were unsafe or too risky to build, e.g. the southern retaining wall seen in section A of s 96 plan 08. Also the size and location of the piling adopted by Mr Green in the structural plans exhibit L differed from the architectural plans. 9 The hearing of this appeal commenced with a site inspection of the subject property and of the adjoining property at 1 Rose Bay Avenue. During the inspection, I heard evidence from one of the owners of that property, Ms J Fletcher (Mr James is the other owner). The hearing then continued in court. Town-planning evidence for the applicant was given by Mr B Kirk and, for the council, by Mr H Sanders. 10 One of the major concerns of the adjoining neighbours of 1 Rose Bay Avenue as set out in their letter of objection to the council dated 3 November 2003 (appendix 3 of exhibit 3) and which was elaborated on by Ms Fletcher related to the proposed significant further excavation of the subject land, which is largely a hillside of sand, above which is the property at 1 Rose Bay Avenue, adjoining the southern boundary of the subject land. Ms Fletcher had serious concerns about the short and long-term impact on the structural integrity of their property. 11 The house at 1 Rose Bay Avenue is a heritage item. According to the evidence of Ms Fletcher, the property is also on the National Heritage Register. The house was designed by Professor L Wilkinson, who was the first professor of architecture in Australia and founded the school of architecture at Sydney University. The house at 1 Rose Bay Avenue is one of his signature residential designs. He also designed the pool and its surrounds, which adjoin the common boundary with the subject land. There is also a tennis court and detached garage on 1 Rose Bay Avenue adjoining the common boundary of the subject land. 12 On the first hearing day, having regard to Ms Fletcher's objection and after considering the approved plans (exhibit 2) and the s 96 plans (exhibit A), I raised as an express issue whether it was appropriate to approve the proposed modification, which would involve significantly more excavation closer to the common boundary with 1 Rose Bay Avenue than was originally approved by the council. I referred the parties to two earlier decisions of mine, copies of which I made available to them: Cawood v Woollahra Municipal Council 10479 of 1988, 25 January 1988 (a case in which Mr R Green gave evidence); Pegasus Construct and Design v Woollahra Municipal Council 10150 of 1997, 6 October 1998. 13 In the present appeal the proposed excavation as seen on the architectural plans is in places to a depth of about 9 m or 10 m below the ground levels shown on the architectural plans; but taking into account the existing ground levels shown on the survey plan (exhibit B) the depth of excavation is in fact greater for the piles and retaining structures. The depth and extent of excavation is far greater than was proposed in the above two cases, and I am not aware of the Court having approved any other proposal for excavation into a hillside of sand for a residential building that would need such massive retaining structures as in this case. The retaining structures for the excavations will comprise principally concrete piles and walers, as well as metal restraining ties or anchors up to 16 m in length passing under the adjoining heritage site. Significantly, some of the piles on the subject land near the boundary of 1 Rose Bay Avenue would have to be constructed in sand to a depth of approximately 20 m. 14 One of the problems that confronted the Court was that the council had refused the s 96 application solely on the ground that the proposed modification would result in a development substantially different from that which was approved. There was no detailed consideration of the impact of the proposed additional excavation and structures near the common boundary of 1 Rose Bay Avenue, because (according to the council) that matter in effect did not arise for consideration because the modification could not be approved if the proposal was substantially different. After the site inspection on the first day, I indicated that I would like to have evidence presented from the council's engineer or from a consulting engineer engaged by the council relating to whether the extent of excavation and manner of retaining it was appropriate, if the Court came to the view that the proposed development would be substantially the same as what was originally consented to. 15 By the second hearing day, the council had retained the services of Mr G Mostyn, civil and geotechnical engineer. He gave joint oral evidence with Mr R Green, structural engineer engaged by the applicant. These two experts prepared a list of conditions, which they thought could be imposed if the Court were to grant consent for the modified development. Those conditions are contained in exhibit H. Having considered the oral evidence and the conditions in exhibit H, I was of the opinion that from a technical and engineering point of view, the conditions were too uncertain and I was not prepared to grant the proposed modified consent. If such a consent was to be granted there would have to be conditions that were more precise and gave greater certainty. Nevertheless, I expressed the tentative view that it might not be appropriate to grant a modified consent having regard to the extent and depth of excavation that was proposed and having regard to the retaining structures would have to be built. The evidence then before the Court indicated that piling would perhaps have to go to a depth of 20 m before a firm foundation could be found. The subject land is a hillside of sand. 16 The applicant then requested an adjournment to enable the applicant's engineer to prepare detailed plans showing how the retaining structures would be built to prevent damage occurring to 1 Rose Avenue from the excavation that would be needed for the proposed modified development. 17 Although the continued hearing of the appeal could have been listed earlier, the parties did not have it brought before me again until 17 September 2004. Two sets of engineering plans were then tendered to the Court. 18 The first set of plans, entitled "Structural" (exhibit L), comprise the following plans prepared by Taylor Thomson Whitting, Job No. 011719B dated 8 September 2004, drawings (each commencing with the prefix "S96") numbered S000 P2, S001 P5, S002 P2, S003 P2, S004 P2, S005 P2, S007 P1. The magnitude of what is involved in retaining and protecting 1 Rose Bay Avenue and in allowing the proposed modified development is particularly disclosed by these plans. 19 The second set of engineering plans, "Civil Works" (exhibit M) comprise the drawings by Taylor Thomson Whitting dated 8 September 2004 numbered C100 P2, C101 P3, C102 P2 and C103 P3. 20 The applicant also tendered a structural specification (exhibit O) and a civil works specification (exhibit P). There were also reports by Douglas Partners dated 8 February 2002, 17 October 2003, August 2004 and 7 September 2004. 21 Oral evidence was given against the proposed modification by Mr A James who is the owner with Ms Fletcher of 1 Rose Bay Avenue. He considered that the originally approved development allowed for a setback and a buffer between the common boundary of 1 Rose Bay Avenue and the subject land, and that the proposed modified development would come too close to the common boundary. Ms Fletcher also gave additional evidence. And I heard further oral evidence jointly from Mr Mostyn and Mr Green. 22 Again, the engineers prepared a set of draft conditions should the Court be minded to grant a modified consent. I set out below these draft conditions: 96 (a) All excavation, and associated engineering works, is to be carried out in accordance with the following documents and drawings: (i) Drawi ngs numbered C100 and C101 (Issue P2, 10.8.04) and C101 and C103 (Issue P3, 08.09.04) entitled "Rose Bay Apartments" (Job No 011719) prepared by Taylor Thomson Whitting (TTW). (ii) Drawings numbered S96/S000 and S96/S002 to S96/S007 (ISSUE p1, 08.09.04) entitled "Rose Bay Apartments" (Job No 011719B) prepared by TTW. (iii) "Civil Works Specifications, Rose Bay Apartments, 577 New South Head Road, Rose Bay, NSW" (Issue P2, 8/9/04, TTW Job No 011719P) prepared by TTW. (iv) "Structural Specifications, Rose Bay Apartments, 577 New South Head Road, Rose Bay, NSW" (Issue P2, 08/09/04, TTW Job No 011719B) prepared by TTW or as amended. (b) The Ap plicant is to provide a monitoring plan for the construction of the piles, excavation and anchors adequate to confirm the design assumptions and to provide forward notice of deformations likely to cause damage. (c) The Applicant is to provide an inspection plan for the various stages of the work adequate to confirm that the construction is such that the intent of the design and any site instruction is met. (d) The Applicant is to provide a report from a suitably qualified engineer proofing the above. (e) Such inspections and monitoring must be carried out by engineers/surveyors independent of the contractor and its subcontractors in accordance with the inspection and monitoring plans. Copies of the inspectors' and monitoring reports must be supplied to the Principal Certifier with 10 working days. Any non-conformity must be immediately conveyed to the Principal Certifier within a Corrective Action Plan. [This condition would replace the council's condition 96.] 97. The written consent of all relevant adjoining property owners is to be obtained to the installation of anchors under their land prior to the commencement of any works on the site and prior to the issue of a Construction Certificate. Evidence of such consent or of a Court order providing such consent is to be submitted with the Construction Certificate Application. 98. There is to be no access from the respective apartments into the light wells on the southern side of the building (other than for maintenance or cleaning purposes) and any openings are to be windows and not doors. Details are to be shown on the drawings submitted with the Construction Certificate Application 23 Assuming it was otherwise appropriate to approve the modified application, a greater degree of certainty would probably be given by the draft conditions in the preceding paragraph than those in the earlier draft in exhibit H. But conditions 96(a)(iv) and (b)–(c) again leave open for determination what will happen if the modelling and other assumptions are incorrect. Messrs Green and Mostyn gave evidence to the effect that one of the purposes of framing the above conditions was to avoid their being involved in advising on future design changes. 24 The draft conditions should also be viewed in the light of the qualifications expressed by Mr Mostyn in oral evidence and having regard to the criticisms in his report dated 16 September 2004 (exhibit 9). 25 Secant piles recommended by Mr Mostyn have not been adopted and the maximum gap between the piles is specified to be 50 mm. I accept the opinion of Mr Mostyn that it is not clear that this narrow gap will be achieved will the very long piles that will be constructed. The possibility of sand loss through those gaps or larger gaps during construction, having an adverse effect on 1 Rose Bay Avenue, if protective measures fail or are not put in place promptly. 26 The earth anchors under 1 Rose Bay Avenue are unlikely to be grounded in rock, and the applicant's engineer accepted that sand anchors would be needed. Mr Mostyn said: "It is my opinion that the drilling [for the anchors] is likely to densify the loose sand and that this is an issue. Further DP [Douglas Partners] analysis predicts lateral movement with no vertical movement and thus the sand is loosened overall." 27 The owners of 1 Rose Bay Avenue were opposed to granting any consent for anchors under their property. 28 It is not clear how long the anchors would remain in place and whether they would be permanent. Mr Green said that the piles would be braced by the proposed residential building and then the anchors could be de-stressed. No doubt this can be done, but the present s 96 architectural plans do not sufficiently show how this bracing would occur, and structural engineering plans would be needed. 29 The Douglas Partners reports provide a prediction of the movement due to wall deflection and anchor stressing. Mr Mostyn commented as follows: · The model adopts an overly optimistic assessment of the elastic modulus for the loose sand (20 MPa), a value of 5 MPa would be more appropriate. · There is no indication of what surface loads have been adopted in the model. I note that 3 m east of the model section there is a 3 m high retaining wall which is likely to lead to higher retaining pressures and deformations. · The fact that there is no vertical movement predicted in these models, indicates to me that the deformation is likely to be very sensitive to the anchor loads and assumed properties. · The DP report states 'Parameters not available have been assumed'; it does not indicate which parameters have been assumed. It appears to me that virtually all the parameters are assumed. The model should be tested for the same anchor loads and different parameters. · The high bond strength adopted on the anchors will probably have induced plastic zones in the soil around the anchor, yet the mesh does not appear fine enough to model this. 30 Mr Mostyn concluded: "It is my opinion that the predicted movements are probably enough to crack the adjacent structures, actual movements may be considerably in excess of these." After the joint conference with Mr Green, Mr Mostyn modified this opinion. But on the evidence, it would still appear that there might be less risk if properly designed retaining structures for the originally approved development (subject to the approved condition 96), or for a modified smaller development, were constructed. 31 Returning to a consideration of the consent dated 28 January 2003, of particular importance is the last condition, condition 96. 32 Prior to the council granting development consent, an inspection committee of the council viewed the site. It appears that the committee was concerned about the impact the proposed excavation would have on the adjoining property at 1 Rose Bay Avenue – a concern that I also had immediately upon inspecting the subject site in the light of what was shown on the plans of the original proposal. On 28 January 2003 a senior assessment officer of the council, Ms K Long, had reported to the Site Inspection Committee as follows: The Site Inspection Committee at its meeting on 22 January 2003 requested that an additional condition to limit the extent of excavation be imposed. The following additional condition is recommended: The outer edge of excavation, piling and all sub-surface walls is to be in accordance with the excavation line and dimensions as marked up on drawing numbered DA12, dated April 2002, drawn by mgt architects. This condition is imposed to protect the adjoining properties. With regard to this condition, the applicant has clearly marked the line of excavation to the outside face of the contiguous pile wall on drawing No. DA12. The dimension from the outside face of the pile to the boundary line would be: · 4250 mm at the closest point to the southern boundary · 4650 mm at the closest point to the northern boundary except at the car park entry where excavation will be to the existing wall · 850 mm to the western boundary · 850 mm to the eastern boundary. It is considered that the recommended additional condition would address the concerns of the Site Inspection Committee with regard to excavation. 33 Regarding the first bullet point of the second last paragraph of Ms Long's report above, the " closest point" of part of the approved building to the southern boundary (that is, to the common boundary with 1 Rose Bay Avenue) is, as she says, 4,250 mm. However, the furthest setback of part of the approved building has the handwritten dimension 9.275 m. This is seen on the plan DA12 (pt ex 2). For a distance of 21.5 m from the eastern side boundary of the subject land along the common boundary of 1 Rose Bay Avenue, the setback from that boundary to the outer face of the line of excavation (indicated by circles representing the continuous piles) is 9.275 m. So the area of setback in the south-eastern section of the subject land from the contiguous piles at the basement level (level 1) on approved plan DA12 (as amended in accordance with condition 96) is 199 sq m. 34 This area of 199 sq m creates a substantial setback from a common boundary, immediately adjoining and below the terrace and pool of 1 Rose Bay Avenue. 35 From the above report of Ms Long it also appears that, in order to obtain the development consent dated 28 January 2003, someone on behalf of the applicant made the changes to plan DA12 limiting the areas of excavation. If that is so, the uncertainty and difficulty in interpreting the consent dated 28 January 2003 arising from condition 96 would appear to be partly the doing of the applicant. 36 The approved plan DA12, as amended in handwriting, indicates that the line of excavation and the outer face of the contiguous piles was not to come closer to the western or eastern side boundaries than 850 mm. The purpose of the side setbacks was apparently to enable deep-soil landscaping between the amended position of the piles and the side boundaries. 37 The interpretation of the development consent having regard to condition 96 is certainly not clear. On one view, condition 96 was intended to apply to all levels even though only plan DA12 was actually amended. On this interpretation, the floors above the basement level that were going to be excavated into the sand hill (and that were going to extend closer to the common boundary with 1 Rose Bay Avenue than the basement level) would have to be cut back and substantial changes made to the upper residential levels. A s 96 application would probably have been needed to give effect to the changes required to be made by condition 96. Alternatively on this view (when the implications of condition 96 are properly understood), the effect of the condition would be tantamount to refusal of the application, because it would not be possible to erect the upper levels that extended closer to the common boundary of 1 Rose Bay Avenue without carrying out excavation (or the placing of piling) in the south-eastern area of 199 sq m referred to above. 38 On another interpretation, it might be argued that the limitation on excavation and on the placing of piling applied only at the basement level shown on DA12 and that other structures, at higher levels of the basement level, could come closer to the side boundaries or to the rear southern boundary. However, this interpretation does not sit comfortably with the express wording of condition 96 where it says that " all sub-surface walls" are to be as marked up on DA12. 39 It was suggested during the evidence of the applicant that the construction of piling did not amount to excavation. However, condition 96 not only limits the carrying out of excavation beyond the line of piling indicated on plan DA12 but also limits the construction of piling within the specified setback areas that are indicated by dimensions on plan DA12. 40 On one view, it would mean that the upper levels of the approved development would have to be amended so that piling could extend down from the existing or finished surface of the land into the positions indicated on DA12. Alternatively, at least at the basement level it was envisaged that there would be no excavation closer to the boundaries than indicated on DA12 at that level. 41 There is also another problem with the consent of 28 January 2003 relating to the eastern side boundary of the site. A number of the habitable rooms of the proposed development rely on light and ventilation being available from the narrow excavated space between the eastern side wall of the proposed building and the eastern boundary. Condition 96 requires the contiguous piles to be moved so as to abut the eastern side wall of the proposed building. This would appear to mean that (at the levels above the basement) the relocated retaining wall or contiguous piles would block out any light or ventilation to the windows in the eastern side wall of the proposed building, where those windows are below the existing level of Cranbrook Lane. 42 Having regard to the matters discussed above and to my findings below, I am of the opinion that the present application for modification of the consent should be refused. 43 A major reason put forward by the Council for refusing the application was that it would be substantially a different development from that which was approved. I have had regard to decide cases such as Moto Projects (No 2) Pty Ltd v North Sydney Council (1999) 106 LGERA 298, which indicate that both a qualitative and quantitative assessment should be made. The changes that would result from an approval of the proposed modifications can be seen in comparing the original approved plans (exhibit 2) with the plans for the modified development (exhibit A). The changes were described by Mr Sanders as follows: · Reduction in the number of units from 11 to 10; · Alterations to internal layout of apartments and apartment mix resulting in 8 x 3 bedroom dwellings and 2 x 4 bedroom dwellings; · Deletion of glazed pedestrian access from Rose Bay Avenue and provision of main pedestrian access and lobby off New South Head Road with secondary access off Rose Bay Avenue; · Reduction in an overall gross floor area of 71.72 m2; · Alteration to building form, roof design and external appearance; · Provision of new courtyards, south side of building, on level three; · Modification to existing tree replacement and amendments to planning design; · Amendments to the volume and line of excavation; · Car parking layout amended and reduction in number of car spaces to 24; · Amendment to Condition 96 relating to the extent of excavation; · Other various modifications as outlined in the Statement of Environmental Effects and shown on Amended Section 96 plans numbered 05 to 08, 10, 12 to 16, LOI and LO2 all dated August 2003. 44 Mr Sanders met with Mr Kirk and they produced a joint statement. They disagreed as to whether the proposal would result in a substantially different development. 45 Although there will be a reduction in the number of units by one, some of the proposed modified units are much larger than the approved one. There has been a small reduction in the overall floor space ratio, but this has been a achieved largely by the deletion of the enclosure for the proposed long walkway across the site from Rose Bay Avenue. In addition, although it is not counted as floor space, larger balconies have been proposed in the modification application for some of the units. Initially, I was of the tentative opinion that notwithstanding the extensive internal changes to the proposal, a finding could be made that the proposed development would be substantially the same as was originally approved. If it had not been for the imposition of condition 96, a finding in favour of the applicant's case could more readily have been made. However, the effect of condition 96 was to limit or reduce the area where excavation and the placing of piling could otherwise occur in accordance with the approved plans. 46 Flying in the face of the requirements of condition 96, not only has there been no reduction in the area where excavation or the placing of piling could occur, but qualitatively if not quantitatively there has been a significant change to the southern side of the proposed development by the extension of the built form towards the common boundary with 1 Rose Bay Avenue. While the amenity impacts for the adjoining property from the built form on the southern side of the proposed modified development would in my opinion not be a sufficient reason as a matter of merit to refuse the application, the increased extension for this built form does involve a greater degree of excavation than what was approved. 47 Mr Kirk asserted that the increased amount of excavation is only 14.2% and that this increase is not significant. However a huge amount of excavation for the whole site was originally proposed, and so in the context of the large site the increased amount of excavation does not appear as a large percentage increase. But what is significant is where the increased excavation would occur – which is close to a property containing a heritage item located on the high side of a sloping, sandy hill. The carrying out of the proposed modified development on that hillside would in my opinion increase to some extent the risk of damage occurring to the structures on that property, because of the substantially greater amount of excavation, particularly in the south-eastern section of the subject land, where the southern walls of the proposed modified units will come much closer to the common boundary. 48 I have therefore concluded that the proposed modified development would be substantially a different development from that which was originally approved by the council. 49 If I am wrong in this conclusion, it does not automatically follow that consent for the modified development should be granted. A finding that a proposed development is substantially the same as the original merely removes the legal bar to the granting of the modification, and it is then necessary to consider whether as a matter of merit the modified development should be approved. 50 In granting the consent dated 28 January 2003 under SEPP 5, the council was also required to have regard to relevant provisions of its own planning instruments that were not inconsistent with SEPP 5. Particularly relevant was cl 28 of the Woollahra Local Environmental Plan 1995: 18 Excavation of land (1) When considering an application for consent for development involving the excavation of any land, the Council shall have regard to how that excavation may temporarily or permanently affect: (a) the amenity of the neighbourhood by way of noise, vibration, dust or other similar circumstances related to the excavation process, and (b) public safety, and (c) vehicle and pedestrian movements, and (d) the heritage significance of any heritage item that may be affected by the proposed excavation and its setting, and (e) natural landforms and vegetation, and (f) natural water runoff patterns. (2) The Council may decline to grant such a consent unless it has considered specialist reports, including geotechnical reports, structural engineering reports, hydrology reports and dilapidation reports of properties which may be affected by the proposed excavation. (3) Consent for an excavation may be granted when consent is granted for any other development proposal for the carrying out of which the excavation is necessary. 51 As well, at the time of the lodgement of the development application, performance criteria P17, P18 and P19 in section 5.2.3 of Residential Development Control Plan 1999 applied: P17 - The building footprint is designed to minimise cut and fill. P18 - The outer edge of excavation, piling and all sub-surface walls shall not be less than 1.5 m from a front, side or rear boundary. P19 - To minimise cut and fill on sloping sites and to encourage good quality internal environments, any habitable room must have at last one external wall fully above existing ground level. It is not clear whether the same provisions still apply, but the criteria would appear to provide reasonable guidelines. It should be noted that not every excavation would be appropriate at only 1.5 m from a boundary. If the building is designed to "minimise cut" , and if the excavation is not deep or is in solid ground, a 1.5 m setback to piling or to a retaining wall would probably be acceptable in most cases. But it is difficult to see that such a setback (or here the engineer's proposed 2 m setback) is at all appropriate in the present case. Moreover, the three performance criteria should be read together. The applicant, and the council in granting the consent dated 28 January 2003, appear to have overlooked P19: "…to encourage good quality internal environments, any habitable room must have at last one external wall fully above existing ground level". Many of the rooms of the approved development and of the proposed modified development fail to meet criterion P19. One external wall of each habitable room should be fully above existing (not finished) ground level. 52 In the proposed modified development, the internal amenity of the habitable rooms on the southern side of the proposed building that are below existing ground level will be improved, but this will be at the expense of a greater excavation closer to 1 Rose Bay Avenue. In my opinion the additional excavation is an unacceptable method of achieving a desirable amenity objective. 53 For the above reasons, the orders of the Court are: 1. The appeal be dismissed. 2. The exhibits may be returned, other than exhibits A, L and 2. ________ A J Nott, Commissioner of the Court DISCLAIMER - Every effort has been made to comply with suppression orders or statutory provisions prohibiting publication that may apply to this judgment or decision. The onus remains on any person using material in the judgment or decision to ensure that the intended use of that material does not breach any such order or provision. Further enquiries may be directed to the Registry of the Court or Tribunal in which it was generated.