Residential Conversion in Leatherhead

Client: Mole Valley District Council

Project Team: BCS Robertson Ltd

Our Role: EA / CA

Project Details

This project involved the conversion of the upper floors of 21 High street Leatherhead into one-bedroom residential apartments. While retaining the existing shop on the ground floor, lower ground and basement floors. The property, previously used as office and banking space, was brought back into use to provide much-needed residential accommodation. The property is located in a Conservation Area and the changes to the fenestrations and external appearance had to be sympathetic and in keeping with the historic character of the building.

Our role included preparing the architectural design, applying for planning permission, preparation of the specifications, contract & tender documentation, contract administration and supervision. Project completion was achieved in mid- January 2026. Works included adapting the existing structure and layout to suit residential use while ensuring compliance with updated Building Safety and Fire Regulations.

Building Safety Act 2022

Although the building measured approximately 8 metres at the front, the presence of a basement unit at the rear which did not initially form part of the development. This increased the overall building height to over 11 metres. Under the BSA and associated fire safety guidance, residential buildings over 11 metres fall within enhanced safety requirements. As a result, the project was required to comply with more stringent fire safety provisions. This included the installation of a new sprinkler system to all five levels of the building. These regulatory changes came into force after the project planning had commenced:

• Requiring design revisions
• A comprehensive fire strategy
• Additional works to ensure full compliance with current legislation.

Challenges

The most significant challenge on the project was the impact of regulatory change to the design and cost of the project. Updated fire safety requirements meant the scope of works had to be amended. Resulting in the addition of a sprinkler system at a cost of approximately £70,000. These changes contributed to the overall project cost doubling from its original estimate. Careful contract administration, cost management, and clear communication with the client were essential in managing expectations and progressing the works compliantly.

Outcome

Despite the challenges, the project was successfully completed and delivered in line with current building safety standards. The former building has been transformed into modern residential accommodation, with fire safety and long-term compliance embedded into the design. This project highlights the practical impact of the Building Safety Act on smaller-scale residential conversions and the importance of early consideration of building height, use, and regulatory thresholds. Get in touch with the Chawton Hill team to find out how we can help deliver your project. To ensure that your project is in line with current building safety and regulatory requirements.