Estimate UK home renovation costs for 2026
Renovation costs in the UK have risen significantly in 2023–2026 due to construction material inflation and labour shortages. These estimates are based on typical 2026 UK trade rates and should be used as a starting point for budgeting — always get 3 quotes from local contractors before committing.
A single-storey rear extension costs roughly £1,800–£3,500/m² depending on specification and location in 2026. A popular 20m² kitchen-diner extension would cost approximately £36,000–£70,000 (higher in London). Double-storey extensions are more cost-effective per m² (~£1,500–£2,500/m²) since the foundations, roof, and scaffolding are shared across two floors. Always add 10–15% for professional fees (architect/structural engineer) and 10% contingency. VAT at 20% is typically applied to the labour and materials unless the property is a new build.
A budget kitchen (e.g., IKEA Faktum or Metod with mid-range appliances) installed costs £8,000–£15,000. A mid-range kitchen (Wren, Howdens, or B&Q premium ranges) with integrated appliances, quartz worktop, and tiling costs £15,000–£30,000. A bespoke or high-end kitchen (Smallbone, Martin Moore, or bespoke joinery) starts at £30,000 and can exceed £70,000. If you're changing the kitchen layout significantly, add £2,000–£5,000 for moving water/waste pipes and rewiring sockets. The biggest cost variables are worktop material and appliance specification.
Velux (roof light) conversions are the cheapest at £20,000–£35,000 — suitable where there's already adequate headroom (1.8m minimum ridge height recommended). A rear dormer adds significant usable floor space and costs £35,000–£60,000 — the most popular type in urban areas. Hip-to-gable conversions (semi-detached houses) run £40,000–£65,000. Mansard conversions involve rebuilding most of the roof structure and cost £55,000–£80,000+. An en-suite bathroom in the loft adds £6,000–£15,000. Structurally sound loft conversions typically increase property values by 10–20% in most UK markets.
In England, many renovations fall under Permitted Development (PD) rights and don't need planning permission: single-storey rear extensions up to 4m (detached) or 3m (other), loft conversions up to 40–50m³, garage conversions, and internal changes. You always need permission for: anything exceeding PD limits; front extensions; work in conservation areas; listed buildings (also need Listed Building Consent); and changes of use. Wales, Scotland, and Northern Ireland have slightly different PD rules. Building Regulations approval is a separate requirement from planning and is almost always needed for structural work, extensions, loft conversions, and new kitchens/bathrooms. Contact your local authority's planning department for definitive advice.
Value uplift varies enormously by location and project. Loft conversions generally have the best ROI, typically adding 10–20% to a property's value (e.g., a £60,000 dormer loft conversion adding a bedroom and en-suite could add £80,000–£120,000 on a £500,000 property in a sought-after area). Single-storey extensions return 5–15% uplift. Kitchen and bathroom renovations return 3–7%, but tired, dated kitchens can hurt a sale more than a great kitchen helps. Energy efficiency improvements (insulation, solar, heat pump) increasingly add value through reduced running costs and better EPC ratings. The golden rule: don't over-capitalise — renovation cost should not exceed the value uplift it creates.