Future Homes Standard transition clock

For ordinary building work, a building can still be built to the previous Part L (2021) if a building notice, an initial notice or a full plans application was given for that building before 24 March 2027, and the work on that building is commenced before 24 March 2028. Both conditions apply building by building (regulation 5 of SI 2026/335). Miss either and the Future Homes Standard applies to that building.

Regulation 46A of the Building Regulations 2010 decides it. For a new building, work counts as commenced when its sub-surface structure, including all foundations, any basement and the structure of the ground floor, is completed. For a complex building (one sharing a podium or plinth with another building, with more than one storey below ground, or a public building for 100 or more visitors) it is when the foundations and the structure of the lowest floor are completed. Site clearance, drainage and roads are not the building's sub-structure, so they don't count.

An application can cover every building on it, but each building has to be commenced in time on its own. A site can end up split, with its early plots on Part L 2021 and its later plots on the Future Homes Standard. If your site has more than one application, check each one separately.

Yes. A full plans approval lapses for any building whose work hasn't commenced within three years from the end of the day the application was made (Building Act 1984, section 32, with commencement judged by the same regulation 46A test). Initial notices lapse in the same way (section 53A), and a building notice stops having effect after three years unless the work has commenced (regulation 13(5)). So anything given before 23 March 2025 runs out before the March 2028 cut-off. Our reading is that a lapsed approval or notice can't carry a plot through the transition, so its lapse date becomes the deadline, and that a fresh application or notice given before 24 March 2027 would restart the three years. Check with your building control body.

No. For higher-risk building work the new rules start on 24 September 2027, and the previous rules continue where a valid application for building control approval was submitted to the Building Safety Regulator before 24 September 2027 and is not rejected. There is no separate commencement deadline. The clock tests that date when you tick the higher-risk box.

No. It checks your dates against the published test and does the arithmetic. Whether a building's work has commenced is for your building control body to decide, so keep the evidence: dated photographs of the finished ground floor structure and the inspection record.