Partial completion at Gateway 3: when it works, and when it will not

What is partial completion for?

Phased developments have a real problem with a hard-stop completion regime: block A finishes a year before block C, and a rule that nothing is occupied until everything is certified would leave finished homes empty on financing that assumed income. The partial completion certificate is the regime's answer: a defined part of the building certified, registered and occupied while construction continues elsewhere, lawfully.

The catch, and it is the entire subject, is that the option only exists if it was designed in. A partial completion strategy must be agreed with the BSR at Gateway 2, defining the parts, their boundaries and the basis on which each can stand alone. No strategy at approval, no phased certificates at completion.

Why is it not suitable for flats or floors?

Because certification follows safety logic, not sales logic. A certified part must work as a safe building in its own right while a construction site operates next to it: fire strategy, evacuation, compartmentation between the occupied part and the works, services that do not depend on uncommissioned plant, and access for both residents and contractors that do not compromise each other. Distinct blocks with their own cores can often satisfy that. A floor in a single-core tower almost never can, which is why the guidance warns against expecting partial completion for individual flats or floors.

The PC versus Gateway 3 gap still applies per part: each phase needs its notice, its evidence, its inspection and its 8-week determination, and the occupied part's registration position must be settled before anyone moves in.

How do you plan a partial completion strategy that survives?

Design the severance first: parts that are genuinely independent for fire, structure and services, with boundaries a reviewer can trace on a drawing. Write the strategy into the Gateway 2 application explicitly, because the approved strategy is the licence for everything that follows. Then run the build so each part's as-built golden thread closes out part by part: the phase you certify first is the phase whose evidence must be finished first, which inverts the usual habit of leaving documentation to the end of the job.

And keep change control honest across the phase boundary. A change in the later works that touches the certified part's fire strategy, its services or its means of escape is not a construction matter in an occupied building; it is a regulatory one. Phased occupation is the regime working as intended, but only for projects that treated it as a design requirement from day one rather than a completion-week negotiation.