AI Mapping Tool Identifies 3,000 Small Sites With Potential for Nearly 10,000 Homes in Lewisham

PropTech pilot points toward a scalable model for unlocking small site housing delivery that could reshape how developers and contractors access pipeline opportunities

Lewisham Council has used an AI-based mapping tool to identify over 3,000 small sites across the borough with development potential, estimating a combined capacity of 9,747 homes. The pilot, funded through MHCLG’s PropTech Innovation Fund round 4, was developed in partnership with architecture and urbanism practice RCKa and represents one of the more substantive applications of AI to small site housing delivery to date.

The Small Sites AI Finder uses artificial intelligence and GIS data to analyse land parcels across the borough, identifying infill, backland and side-street sites and estimating their housing capacity. The tool was trained on examples of typical small site shapes and sizes within freehold boundaries, with Ordnance Survey mapping data used to improve accuracy. Alongside the site identification work, Lewisham analysed planning application data to assess the impact of its Small Sites Design Guide SPD on delivery outcomes, finding modest improvements in approval rates following its adoption.

For construction and development supply chain businesses, the pilot’s significance lies less in its Lewisham-specific outputs and more in what it signals about how local authorities are beginning to systematise small site identification at scale. Small sites have historically been difficult to identify and aggregate efficiently, with officer knowledge and manual review forming the primary discovery mechanism. A tool capable of mapping thousands of sites across a borough in a structured, repeatable way changes the economics of small site pipeline development – for councils, registered providers, SME housebuilders and the contractors who serve them.

The accuracy findings are worth noting. Identification rates varied between 31% and 76% depending on site type, and the council is clear that officer review remains essential – the tool supports professional judgement rather than replacing it. Processing Ordnance Survey data also added time to the project, a constraint that will need to be addressed before the approach scales efficiently.

Lewisham’s housing delivery team is now actively exploring opportunities identified by the tool, considering sites suitable for future delivery or land disposal. The council plans to develop the finder further to support targeted landowner engagement and inform future updates to its Small Sites Design Guide SPD.

MHCLG’s publication of the pilot as a case study suggests the department sees it as a model with broader applicability. For developers and contractors focused on small and medium site delivery, the direction of travel is toward local authorities arriving at conversations with landowners and housebuilders with a far more structured view of their small site opportunity pipeline than has historically been the case.