How much does external wall insulation cost in 2026?
The short answer
In 2026, external wall insulation typically costs around £109–£175 per square metre for the system and finish, plus scaffolding. For an average home our guide prices are about £8,595–£11,695 for a mid-terrace, £13,995–£19,195 for a three-bed semi and £20,495–£28,095 for a four-bed detached house, with VAT at 0% on homes until 31 March 2027.
Guide prices by house type
Guide ranges for an average-sized home with EPS insulation and a silicone render finish, including scaffolding and standard details. They are not quotes: your survey sets the fixed price, and the guide-price tool adjusts for size, board and finish using the same figures.
| Home | Average wall area | Guide price (0% VAT) |
|---|---|---|
| Mid-terrace house | ≈65m² | £8,595–£11,695 |
| End-terrace house | ≈105m² | £13,195–£18,095 |
| Semi-detached house (3-bed) | ≈110m² | £13,995–£19,195 |
| Detached house (4-bed) | ≈165m² | £20,495–£28,095 |
| Detached bungalow | ≈90m² | £10,995–£15,295 |
| Park home (twin unit) | ≈55m² | £6,795–£9,395 |
Guide prices per square metre
| System and finish | Per m² (system and finish) |
|---|---|
| EPS + silicone render | £109–£149 |
| EPS + pebbledash | £115–£159 |
| Mineral wool + mineral or silicone render | £129–£175 |
| Phenolic + silicone render | £135–£185 |
| Insulated cladding | £145–£225 |
| Wood fibre + lime or mineral render | £155–£215 |
| Brick slip finish | £185–£265 |
| Insulating lime render (no boards) | £95–£145 |
Per square metre rates cover the insulation system, finish and standard details; scaffolding and set-up are priced per house. Published 2026 figures vary widely. The Federation of Master Builders quotes around £85–£130 per m²; other 2026 guides put typical all-in costs nearer £150–£200 per m². The spread reflects region, access, finish and how much detailing each figure includes.
What makes the price go up or down?
- Wall area and shape: bays, gables and lots of openings take longer than plain walls.
- Board: mineral wool, phenolic and wood fibre cost more than EPS.
- Finish: brick slips and cladding cost more than render.
- Details: roofline extensions, moving gas meters, deep reveals and conservatory junctions add cost.
- Access: scaffolding over roofs, footpath licences and narrow passages.
- Wall condition: removing loose render or repairing brickwork first.
VAT on external wall insulation
Installing insulation in a home is zero-rated for VAT until 31 March 2027, after which the rate is due to return to 5%. Commercial (non-residential) work is standard-rated. Our home prices are shown with VAT at 0%.
Related services
Questions people ask
Is scaffolding included in EWI prices?
Our whole-house guide prices include standard scaffolding; per square metre rates don't, because scaffolding is priced per house. Unusual access, such as scaffolding over a conservatory or a council footpath licence, is priced at survey.
Why do EWI quotes vary so much?
Quotes differ in board thickness, finish, how many details are included and whether the roofline, sills and services are dealt with properly. Compare like with like.
Can I pay in stages?
Yes. Our standard terms are a 50% deposit when you accept the quote, 40% on the first day of installation and the 10% balance on satisfactory completion, set out in writing with your quote.