About Part L Checker

Part L Checker is an AI-powered compliance tool that helps builders, contractors, and site managers verify photographic evidence against Part L of the UK Building Regulations (Conservation of Fuel and Power) and, specifically, the Appendix B photographic evidence requirements for thermal junctions.

On site, a user photographs a thermal junction — a lintel, sill, jamb, eaves, party wall, or any of the E1–E25 detail types — and the app analyses the image like a senior UK Building Control Officer with 25 years of experience. Within seconds it returns a clear PASS, MARGINAL, or FAIL verdict, a confidence score, and specific, practical guidance on what to fix and how to photograph the detail better, so evidence is right the first time and costly re-submissions are avoided.

It is built for the people who carry the risk of compliance on residential and commercial sites: builders and contractors preparing evidence for building control, site managers quality-checking work before it is concealed, and developers who need a structured, auditable record of thermal junction evidence organised by project and numbered plot. Approved images can be sent individually or in bulk to a building control platform — appb.co.uk — and tracked from sent to confirmed, closing the loop between site and submission.

Part L Checker is built by a specialist team working at the intersection of construction and software, focused on using practical AI to reduce the paperwork, rework, and delay that compliance evidence creates for the construction industry.