Mr Paul Rodger: Demolition of Detached Dwellinghouse, Erection of 3 Detached Dwellinghouses and Formation of Vehicular Access: Peat Knowe, Back Road, Clynder, Helensburgh (Ref: 21/01943/Pp)
Argyll and Bute Council · 28 September 2022
Back to Planning, Protective Services and Licensing Committee — 28 September 2022 and its agenda
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Argyll and Bute Council Development and Economic Growth Delegated or Committee Planning Application Report and Report of Handling as required by Schedule 2 of the Town and Country Planning (Development Management Procedure) (Scotland) Regulations 2013 relative to applications for Planning Permission or Planning Permission in Principle _________________________________________________________________________ Reference No: 21/01943/PP Planning Hierarchy: Local Application Applicant: Mr Paul Rodger Proposal: Demolition of detached dwellinghouse, erection of 3 detached dwellinghouses and formation of vehicular access Site Address: Peat Knowe, Back Road, Clynder, Helensburgh, Argyll and Bute G84 0QF ________________________________________________________________________ SUPPLEMENTARY REPORT NO. 3 1.0 INTRODUCTION The attention of Members is drawn to the main Report of Handling dated 8th June 2022 that is currently before them for consideration in respect of the above application and the Supplementary Report No.2 dated 16th August 2022, on the main agenda. At the PPSL meeting on 22nd June, the Council agreed to continue consideration of this application at their next available meeting in August 2022 and instructed Officers to request that the Applicant provide, by the end of July 2022, an engineering report on the ground engineering works required to ensure stability of the sloping ground to prevent any slippage or flooding onto neighbouring properties. A Supplementary Report no.2 was presented to the August meeting of the PPSL advising members the requested Civil Engineering Report had not been received within the timescale required to report this to the August PPSL. However, the agent gave an assurance that the Civil Engineering Report (to address the issues raised by the PPSL Committee at the June meeting) would be submitted before the deadline of 26/8/22 at the latest (in order to allow the proposed development to be fully considered by Members at the September PPSL Committee.) The Supplementary Report No.2 also included a summary of additional considerations and clarification of previously raised issues arising from a letter of objection submitted after the June PPSL meeting. At the August meeting, in response to the Supplementary Report No.2, the Committee: 1. agreed that consideration of this planning application be continued to the September PPSL Committee to allow the applicant the extended opportunity to prepare and submit the Civil Engineering Report requested; and
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2. noted that Planning Officers would undertake to carry out any further investigations required in response to concerns expressed by local residents and report back to the next available PPSL Committee. 2.0 SUMMARY OF DEVELOPMENTS Pursuant to the decision made by Members at the June PPSL Committee, the additional information requested from the applicant has been received on 24th August 2022: - 1) Letter dated 23rd August from Ardmore Point Ltd. to the applicant’s agent 2) Phase 1 Desk Study Report by Ardmore Point Ltd. – Issue 1 – July 2022 3) Phase 2 Ground Investigation Report by Ardmore Point Ltd. – Issue 1 – August 2022 The applicant’s consultant, Ardmore Point Ltd. provides Geomatics, Geotechnical, Drone UAV and Construction Management Services. 3.0 SUMMARY OF ADDITIONAL SUPPORTING INFORMATION The covering letter and the Phase 1 and Phase 2 Reports are available for inspection in full on the planning application file, however this information is summarised below for members convenience. Applicant’s consultant’s covering letter (23.08.2022) The ground conditions on the site are “stiff glacial till clay overlying shallow bedrock” (based on a review of the ground condition data now received from the ground investigation boreholes and testing , the site topographical survey and the proposed levels layout.) Confirmation that “subject to a suitably designed retaining wall to the front the ground would be stable for the intended road development” (based on an understanding of the proposed development layout with houses sited to the rear and an access road along the front of the site). Confirmation that the site is stable in its current state. Phase 1 Desk Study Report – Summary of Conclusions Current use (on the basis of a walkover survey carried out in July 2022) is derelict awaiting redevelopment with an existing house; a mix of hard and soft landscaping with gently sloping topography. A Flood Risk Assessment is outside of the scope of this report. It is considered that “the site has “passed” with minimal risk to flooding.” Made ground could be a potential source of ground gas on site – risk to local ecology from potential contamination is low. The “Landmark” Report makes no reference to sources of potential ground gas. Landfill gas unlikely to be present. Site is in “lower probability Radon area – no Radon protection measures are necessary in relation to construction.” Phase 2 Ground Investigation Report – Summary of Conclusions Work carried out 09.08.2022-11.08.2022 comprising boreholes, in-situ testing, sampling, gas and water monitoring installations. The borehole plan indicates 3 no. boreholes at regular intervals along the top of the ‘built up’ bank adjacent to the front of the site (BH02, WS02 & BH04); 4 no. regularly spaced boreholes along the rear part of the site; and 1 no. adjacent to the site access
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at the south east corner of the site. Boreholes BH02, WS02 & BH04 were terminated at 4.03m, 4.0m & 3.0 respectively due to Mudstone/Sandstone obstruction. Intrusive ground investigation revealed made ground (concrete) in only 1 no. borehole from 0.00-0.10m. Superficial deposits of sandy, gravelly silt with clay to a maximum depth of 3.80m was recorded consistently across the site in all boreholes. Bedrock, or possible bedrock, was encountered across the site as sandstone and mudstone recorded from 2.80m x 3.90m variable depth. Groundwater was not encountered. No areas of ecological or archaeological significance were encountered. Due to ground conditions, infiltration-based soakaways are unsuitable for this site. From the proposed site plan, levels will be reduced by approximately 900mm when the driveway is constructed. Proposed Finished Floor Levels (houses) will be typically 200mm above existing ground levels and foundations will be at the shallowest convenient depth. From inspection of ground conditions, the boulder clay encountered at 1.20m depth would be classed as “stiff to very stiff” with potential bearing capacity in the order of approximately 100kN/m2. 4.0 ASSESSMENT The additional information requested by Members at the June PPSL meeting has now been submitted by an appropriately qualified and experienced consultant and in accordance with British Standards and all normative references. The contents of the covering letter from Ardmore Point Ltd. are self-explanatory. It is noted that the Phase 1 Survey is limited to a ‘desktop assessment’ of relevant information and documentation already available supplemented by a walkover survey in July 2022. The description of the current site use at para. 4.2, 4.3 & 4.4 is not accepted by planning officers. The site has been stripped of any soft landscaping including trees, hedgerows, shrubs and grass as part of land engineering works. The topography of the site is not “gently sloping” but has a very steep and relatively high excavated bank along the rear boundary and ground made up from the spoil from that excavation along the front of the site including a high bank along the front edge of the site adjacent to the rear boundaries of existing residential properties. It is noted that the Phase 1 Survey does not include a Flood Risk Assessment. The assessment on flood risk is based on records held by regulatory authorities and statutory bodies to determine prevalent hydrological features on or within 250m of the site. The Report does not specifically address the groundworks and clearance of natural vegetation on the site and any consequent increased risk of flooding affecting nearby property and roads. It is also noted that the Phase 1 Report does not address issues of ground stability, either in respect of the proposed development or the existing site condition following significant re- contouring of ground levels. The conclusions of the Phase 1 Report are generally accepted with the exceptions of the description of the current site topography/landscaping the observation that it does not address issues of flooding outside of the site or ground stability.
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The Phase 2 Report is perhaps more informative in that the assessment is based on in-situ testing and intrusive ground investigation including boreholes. It is noted that 3 no. boreholes were located at regular intervals along the top of the banked material used to build up the ground level adjacent to the front (north eastern) site boundary. It is considered that the conclusions as set out in the covering letter from the applicants consultant, Ardmore Point Ltd., based on the desk-top and site investigation survey information provides adequate assurances that; - 1) The existing site is stable in its current state; and, 2) “Subject to a suitably designed retaining wall to the front” the ground would be stable for the intended road development. On this basis it is recommended that the application be approved in line with the original recommendation as presented to Members at the June PPSL Committee meeting. In addition, it is considered that the representations received subsequent to the June meeting of the PPSL do not raise any further material planning considerations such as would warrant the refusal of this application for planning permission. On the basis of the assessment as set out in the original Report to the June meeting of the Committee and the assessment in relation to the additional supporting information submitted, subject to planning conditions, it is considered that the proposed development is in accordance with the relevant provisions of the Argyll and Bute Local Development Plan – 2015 and all other associated guidance. 5.0 RECOMMENDATION It is recommended that planning permission be approved, subject to conditions and advisory notes as set out in full in the main Report (June PPSL meeting) with the exception of an additional planning condition as follows: - “Notwithstanding the provisions of Condition 1, no development shall commence until full technical construction details of the proposed retaining wall, including the means of vehicle restraint, directly adjacent to the east of the proposed shared roadway have been submitted to and approved in writing by the Planning Authority. The retaining wall and vehicle restraint barrier shall be implemented in full in accordance with the approved details prior to commencement of any other development on the site in relation to the construction of any roads/driveways or the construction of the houses including ground excavation, and shall be retained and maintained to the satisfaction of the planning authority unless otherwise agreed in writing by the planning authority. Reason: To ensure that the proposed development does not result in any ground instability by reason of excavation and land-raising engineering operations carried out as part of this development, and to protect adjacent land and property from potential damage by reason of unstable ground conditions.” Author of Report: Norman Shewan Date: 9th September 2022 Reviewing Officer: Howard Young Date: 9th September 2022 Fergus Murray Head of Development and Economic Growth