Building your own home? Many self-builders assume they pay 20% VAT throughout and reclaim it all at the end. That is not how the new-build rules work. Contractor services should normally be zero-rated — VAT431NB is principally for reclaiming VAT on materials you bought directly.
The final VAT431NB claim is not a general refund of every VAT charge connected with the project. HMRC is clear: VAT charged incorrectly on contractor services cannot be reclaimed through the DIY scheme. Where VAT has been applied to work that should have been zero-rated, the supplier must correct it.
Each page below gives a direct answer, the HMRC basis, and a practical checklist.
Qualifying new-build construction services should be zero-rated. 20% on services is an overcharge.
Check whether your property type, planning permission and intended use meet HMRC's eligibility rules.
Direct materials at 20% — and what is excluded (contractor overcharges, professional fees, carpets, appliances).
6 months from the completion certificate. No exceptions. Find out exactly when your clock starts.
You need valid VAT invoices for every purchase. Find out what you can recover and what cannot be claimed.
Now is the last chance to fix contractor VAT errors and chase missing documents before the clock starts.
HMRC has specific requirements. Card receipts and bank statements are not enough.
Not through VAT431NB. Incorrectly charged VAT must be corrected by the supplier — find out how.
VATBuild asks the key questions about your project — planning permission, intended use, claimant type, occupancy conditions — and maps your project to the correct HMRC VAT treatment before you upload a single invoice.
Every contractor invoice is reviewed against the expected rate. On a new build, qualifying services should be 0% — VATBuild flags any invoice showing 20% as a potential overcharge requiring supplier correction.
Each line item is classified: reclaimable direct materials, excluded goods, contractor overcharges requiring correction, and professional fees. No manual sorting spreadsheet required.
Once you enter your completion certificate date, VATBuild calculates your VAT431NB submission deadline and surfaces it prominently — alongside a list of outstanding issues to resolve before you submit.
Every line item in your claim is documented with its VAT classification, the applicable HMRC Notice 708 rule, and a plain-English reason — a claim summary your accountant can verify and HMRC can follow.
VAT431NB applies to new-build dwellings only — not renovations or extensions.
VATBuild is likely to provide the greatest value where the build budget exceeds approximately £300,000, several VAT-registered suppliers are involved, you approve invoices personally, and nobody is independently reviewing the complete VAT position. That describes the typical self-builder exposed to errors across contractor invoices, direct purchases, evidence and the final claim.
VATBuild works at any point in the project.
Set up the eligibility record, review planning conditions and understand the distinction between contractor zero-rating and your VAT431NB material claim.
Check how contractors intend to treat VAT before their prices are accepted. Catching rate errors at quotation stage is far easier than after invoices are issued.
Upload invoices as they arrive, separate eligible materials from excluded items and identify contractor VAT that may need correction.
Review the claim schedule, missing invoices, supplier corrections and completion evidence before the 6-month window begins.
Confirm the relevant completion date and act promptly. The 6-month VAT431NB submission window starts from your completion certificate date.
Most preventable self-build VAT problems arise before the final claim: a contractor charges 20% instead of 0%, an invoice is issued to the wrong person, a merchant receipt is not a valid VAT invoice. Your VAT431NB claim is a one-shot opportunity — use VATBuild to build the record throughout construction.
VATBuild is a construction-VAT decision-support and evidence-management platform. It is not HMRC and does not guarantee eligibility or repayment. The correct treatment depends on the project, planning position, supplier, expenditure and evidence. Always consult a qualified accountant or tax adviser before submitting an HMRC claim.