Self BuildersConversion VAT Reclaim
Converting a barn, office, pub or chapel into a home? HMRC's VAT431C scheme lets you reclaim VAT on your conversion — but only if contractor invoices are correctly rated at 5%, all documents are in order, and the claim is submitted within 6 months of your completion certificate. Most conversions have reclaimable VAT of £15,000 to £40,000. Most also have at least one invoice problem that reduces it. VATBuild finds those problems before they cost you money.
On a qualifying residential conversion, contractor building services must be charged at the 5% reduced rate under HMRC Notice 708 — not 20% standard rate. The difference is not reclaimable via VAT431C. It can only be recovered by getting the contractor to reissue a corrected invoice.
The £30,000 shown above is not lost to HMRC — it was overpaid to the contractor. But recovering it requires the contractor to issue a credit note and corrected invoice, adjust their own VAT return, and refund you the difference. This becomes significantly harder once the project is finished and the contractor has moved on.
Read more: My builder charged 20% — is that correct?Most people treat VAT431C as a form you fill in after completion. That is too late for some of the most significant issues.
Rate errors on contractor invoices can only be corrected while the contractor is still actively involved in your project.
Missing VAT receipts from builders' merchants become harder to replace as time passes — some systems retain records for 12 months or less.
Contractor VAT number problems can invalidate an invoice entirely — catching them early means a corrected invoice, not a missing claim.
Invoices for works in the wrong period (before planning permission or after completion) need to be identified and excluded — not discovered at submission.
Each card links to a detailed answer covering the HMRC rules, the distinction that matters, and what to do next.
On a qualifying conversion, contractor services should be 5%. 20% is an overcharge.
Check whether your building type and previous use meet HMRC's eligibility rules.
Contractor services, direct materials — and what is excluded (carpets, fees, furniture).
6 months from the completion certificate. No exceptions. Find out when your clock starts.
You need valid VAT invoices. Find out what you can recover and what cannot be claimed.
Now is the last chance to fix VAT rate errors and chase missing documents.
Your planning decision notice is a required document for VAT431C. Find out exactly what to include.
Yes. It is required — and it starts the 6-month deadline clock.
Each building type has its own VAT complications. Select yours for a guide that covers the specific eligibility questions, VAT rate rules, and HMRC evidence requirements for that conversion type.
Agricultural buildings, mixed farm use, drainage and site infrastructure — the specific complications on barn projects.
Former pubs, restaurants, offices and retail units — including the mixed-use living-quarters complication.
Former religious buildings — listed building constraints, specialist conservation works, and common rate errors.
Former schools and colleges — caretaker accommodation exclusions, large-footprint rules, and multiple-dwelling conversions.
Properties empty for 10+ years — the 10-year rule, evidence requirements, and how this route differs from standard conversions.
Former factories, warehouses and industrial units — structural investment, groundworks complications, and services fit-out.
VATBuild asks the key questions about your project — building type, previous use, planning status, claimant type — and maps your project to the correct HMRC VAT treatment before you upload a single invoice.
Every contractor invoice is reviewed for the expected VAT rate. On a conversion, services should be 5% — VATBuild flags any invoice showing 20% as a potential overcharge requiring supplier correction.
Each line item is classified: claimable contractor services, claimable direct materials, excluded items (professional fees, carpets, white goods). No manual sorting spreadsheet required.
Once you enter your completion certificate date, VATBuild calculates your VAT431C 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.
VATBuild is useful at every stage of a conversion.
Set up your project, confirm your VAT scheme, and understand what HMRC expects — before any money is spent.
Upload invoices as they arrive. VATBuild checks each one and flags any VAT rate errors or missing information.
Run a full pre-claim readiness check. Identify outstanding issues before the completion certificate is issued.
Generate a structured VAT431C claim summary with every line item explained. Submit to HMRC with confidence.
Your VAT431C claim happens once, within 6 months of completion. Set up your project free — start catching invoice problems from day one.