How long you have to claim self-build VAT
The rules changed in December 2023, and a lot of what's online still reflects the old ones.
The current position
If your build completed on or after 5 December 2023, you have six months from completion to submit. If it completed before that, the old three-month window applies.
You get one claim. Not one a year, not one per phase — one, covering everything, submitted once.
What counts as completion
Usually the date on your building regulation completion certificate. But it has been litigated repeatedly, and it isn't always the certificate date — occupation, a habitation letter or the finishing of works have all been argued.
If your completion date is at all ambiguous, or the deadline is close, that's a question for a professional rather than a website.
Why it catches people
The claim is the last thing on your mind when you finally move in. Six months feels generous until you're chasing a merchant who no longer has your invoice on their system, for goods bought two years earlier, while living in a house that still needs skirting boards.
The work isn't the form. It's assembling two years of invoices and getting the defective ones corrected — and that gets harder every month you leave it.
What to do now
If you're mid-build, check your invoices as they arrive. If you've finished, work out your date today and count forward. If you're past it, a late claim needs a written explanation and HMRC isn't obliged to accept it — but it's worth asking rather than assuming.