Phase 1 Desk Study for an Office Redevelopment, Longfield

Lustre Consulting was instructed by DHA to undertake a Phase 1 Desk Study for Ash House, a two-storey office building located in New Ash Green, Kent. The project proposed the conversion of the existing commercial space into 14 residential apartments, requiring detailed environmental assessment to ensure compliance with planning regulations and address any potential contamination risks.

Given the site’s history and its proximity to sensitive receptors, our comprehensive Phase 1 Desk Study provided insights to support the planning application and safeguard the redevelopment process.

Site Overview and Development Context

The redevelopment project involved:

• Proposed Conversion: Transforming the former office building into residential apartments while retaining the building’s structural footprint.
  
• Landscaping Enhancements: Minor modifications to create soft verges, parking spaces, and access routes.
  
• Environmental Sensitivity: The site is situated near groundwater aquifers, making it critical to evaluate potential contamination risks from historical land uses.

Due to the location of Ash House, combined with its historical use as agricultural land, required a targeted environmental assessment to identify and address any potential contamination risks.

Phase 1 Desk Study: Methodology and Findings

Lustre Consulting’s Phase 1 Desk Study combined historical research, site surveys, and regulatory data reviews to deliver a thorough risk assessment. Key elements included:

• Historical Land Use Analysis: Our review of historical Ordnance Survey maps revealed that the site was previously used as agricultural land and orchards. Such uses are often associated with residual pesticides and herbicides in the soil, requiring careful assessment to rule out risks to human health and groundwater.
  
• Regulatory Data Review: We assessed publicly available environmental records, focusing on historical pollution incidents, nearby industrial activities, and waste facilities. While no major pollution sources were identified in close proximity to the site, minor risks from offsite facilities were noted.
  
• Environmental and Geological Assessment: Geological data indicated a mix of clayey subsoils with potential imported materials used during the construction of Ash House in the 1980s. These materials could pose risks of localised contamination. Additionally, the site’s proximity to a groundwater aquifer increased its environmental sensitivity.
  
• Site Walkover Survey: During our site visit, we observed existing hardstanding surfaces and car parking areas, which showed no visible signs of contamination, such as oil staining or hazardous material storage. However, the use of the car park over time introduced minor risks from potential hydrocarbon leaks.

Supporting Planning Approval

The findings from our Phase 1 Desk Study were compiled into a detailed report submitted to Sevenoaks District Council. By addressing potential contamination risks and providing clear mitigation strategies, Lustre Consulting’s work provided the necessary assurances to support the planning application.

Our thorough desk study supported the planning application, paving the way for the conversion of Ash House into high-quality residential apartments that meet environmental and safety standards.