GUIDE
VAT on home works — display choice, not a ruling
Last checked September 2026 · Published by Rodway Labs
Not a quote. Figures in this guide are illustrative UK cost bands compiled for planning. They are not a tender, valuation or building-regulation ruling. Get written quotes for the property. Project Cost Lab (Rodway Labs) is not a contractor, architect or quantity surveyor. The mid figure is a band, not a price; the VAT toggle is a display choice, not a ruling.
What this site does with VAT
The calculator includes a VAT control so you can view an illustrated band with 20% VAT, 5% VAT, 0% VAT, or ex-VAT. That control exists because homeowners compare quotes that present tax differently. It does not decide the rate that applies to your supplier, your property or your invoice.
Typical patterns (illustrative, not advice)
- Most work on an existing dwelling is standard-rated in everyday domestic improvements — extensions, loft conversions, kitchens and bathrooms often appear with 20% VAT on labour and materials from VAT-registered contractors.
- New dwellings and certain qualifying conversions can sit under different regimes. Whether your project qualifies is a facts-and-law question for the supplier and advisers — not for a web slider.
- Some energy-saving measures may attract reduced or zero rates when conditions are met. Heat pumps, insulation and other measures are often discussed in that context; eligibility is not automatic.
Rodway Labs does not provide tax advice. If VAT treatment materially changes your budget, confirm it in writing on the quote.
Why the mid band can mislead if you ignore VAT
Comparing an ex-VAT shell quote with an inc-VAT turnkey quote is a classic way to think you have saved money when you have only changed presentation. Always ask: is the figure ex-VAT or inc-VAT, and which rate has the contractor applied?
In Project Cost Lab, pick the display that matches how you want to plan, then re-run when a quote states a different treatment. Contingency still sits on top of the illustrated total in the model.
What VAT does not fix
VAT treatment does not repair soft ground, Party Wall awards or under-specified glazing. Those remain outside or as optional allowances. Regional and access factors still apply to the works mid before tax display.
Practical checklist
- Ask every quote to state VAT rate and whether prices are ex or inc.
- Do not assume reduced rates for “eco” branding alone.
- Use this site’s VAT toggle only to align the planning band with the quote format.
- Keep a contingency even when VAT looks favourable.