VAT on Building Work: What You'll Actually Pay

VAT adds 20% to the cost of almost all building work on existing UK homes - and it's the single most common surprise in builder quotes. Whether you're planning an extension, a loft conversion, or a full renovation, understanding how VAT applies helps you budget accurately and compare quotes fairly.

The Basic Rules

Standard Rate (20%) - Most Building Work

The vast majority of work on existing residential properties is charged at the standard 20% VAT rate:

• Extensions (single-storey, double-storey, wrap-around)
• Loft conversions
• Garage conversions
• Basement conversions
• Kitchen and bathroom refits
• Rewiring
• New boiler and heating
• Plastering and decoration
• Roofing repairs and replacement
• Window and door replacement
• Landscaping and driveways
• All professional fees (architect, engineer, planning)

Reduced Rate (5%) - Specific Situations

A handful of scenarios qualify for 5% VAT instead of 20%:

Check the full list on HMRC's VAT guidance for construction.

Zero Rate (0%) - New Builds Only

Zero-rate VAT applies to the construction of a brand-new dwelling - not to work on existing homes. This includes:

• New-build houses and flats
• Self-build projects (VAT reclaimable after completion)
• Conversions creating a new dwelling from a non-residential building (materials at 0%, labour at 5%)

This does not apply to extensions. Adding rooms to your existing home is standard-rated work, no matter how substantial.

How VAT Affects Your Budget

The Impact on a Typical Extension

That's nearly £11,000 in VAT on a mid-range extension. This is not a rounding error - it's a significant budget line that must be planned for.

VAT-Registered vs Non-Registered Builders

Important nuance: Non-VAT-registered builders still pay VAT on the materials they buy, so their material costs are higher relative to their quote. The saving to you is on the labour element and their profit margin. The overall saving is real but less than 20% of the total.

Using a non-registered builder purely to avoid VAT is not a sound strategy. Choose builders on quality, experience, and references first. The VAT status is a secondary consideration. Find quality-assessed builders through the Federation of Master Builders or TrustMark.

Reading Builder Quotes: VAT Traps

Trap 1: "Plus VAT" in Small Print

Some quotes present the headline figure excluding VAT, with "plus VAT" buried in the terms. Always ask: "Is this price inclusive or exclusive of VAT?"

A £9,000 difference on the same number. See our guide to builder quotes for more on what to check.

Trap 2: Comparing Registered and Unregistered

When comparing quotes from a VAT-registered builder (£48,000 inc VAT) and an unregistered builder (£42,000), the price difference is only £6,000 (12%) - not the £8,000 (20%) it appears. The unregistered builder's materials already include irrecoverable VAT.

Always compare total inclusive prices when evaluating quotes.

Trap 3: Subcontractor VAT

Your main builder may be VAT-registered, but some subcontractors (electricians, plumbers, plasterers) may not be. The main builder charges you 20% VAT on the full invoice including subcontractor work. This is correct and legal - the VAT status of subcontractors is irrelevant to what you pay.

Energy-Saving Work: Special VAT Rules

Since 2022, certain energy-saving installations benefit from reduced or zero-rate VAT:

The zero VAT rate on insulation, solar panels, and heat pumps was introduced in April 2022 and is due to remain until at least April 2027. Check HMRC's current guidance for the latest position.

The Self-Build VAT Refund

If you're building a completely new dwelling (not an extension), you can reclaim VAT on materials through HMRC's DIY Housebuilders scheme:

• Eligible: New-build homes, including self-build
• Not eligible: Extensions, renovations, or alterations to existing homes
• Claim deadline: Within 3 months of completion
• Evidence needed: All VAT invoices, planning permission, Building Control completion certificate
• Typical refund: £15,000-£40,000 for a self-build home

This is a one-off claim after the build is complete - you cannot claim incrementally during construction.

Practical Tips

1. Budget for VAT from Day One

Add 20% to every cost estimate that doesn't explicitly state "inc. VAT." Our renovation budget checklist includes VAT in all figures, but if you're working from raw builder quotes, check each one.

2. Ask Every Professional

When appointing an architect, engineer, surveyor, or consultant: "Are your fees inclusive or exclusive of VAT?" Don't assume.

3. Don't Chase VAT Savings

Choosing a builder solely because they're not VAT-registered is false economy if they lack the experience, insurance, or track record of a larger firm. The potential savings (£5,000-£10,000) are dwarfed by the cost of poor workmanship or a builder who disappears mid-project. See our contracts guide for proper protection.

4. Check Energy-Saving Rates

If your project includes insulation, solar panels, or a heat pump, ensure your installer applies the correct 0% VAT rate. Some installers mistakenly charge 20% on qualifying work.

5. Keep All VAT Invoices

Even though you can't normally reclaim VAT on residential work, keep all invoices. They're essential for insurance claims, warranty claims, and proving costs if you sell the property and need to demonstrate the value of improvements for capital gains calculations.

Next Steps

1. Check every quote - ask "Is this price inclusive of VAT?"
2. Budget 20% on top of any ex-VAT figures
3. Compare quotes on an inc-VAT basis - see our quoting guide
4. Check energy-saving VAT rates - HMRC guidance has the latest rules
5. Get a cost estimate - our free calculator shows costs inclusive of VAT
6. Read our budget checklist for the full cost picture