Cost guide
How much does external wall insulation cost?
Last updated 11 July 2026
External wall insulation costs £130–£190 per m² installed in 2026, with grants of up to £15,000 for qualifying solid-wall homes. It cuts heating bills 25–40% — the Energy Saving Trust estimates £300–£500 a year saved on a semi-detached — while giving the house a completely new facade.
Price by house type
| House type | Typical price | Duration |
|---|---|---|
| 2-bed terrace | £8,000–£13,000 | 1.5–2 weeks |
| 3-bed semi-detached | £11,000–£17,000 | 2 weeks |
| 4-bed detached | £16,000–£25,000 | 2.5–3 weeks |
Prices updated 11 July 2026 · includes scaffold, materials, labour and waste.
Current per-m² rates
| Work | Typical price |
|---|---|
| External wall insulation | £130–£190 per m² |
Prices updated 11 July 2026 · Every project is quoted individually after a free survey.
What the per-m² price includes
£130–£190 per m² covers the full system: 60–150mm insulation boards (EPS, mineral wool or phenolic), mechanical fixings and adhesive, basecoat with reinforcement mesh, and a silicone or mineral render finish in your chosen colour. Scaffold, beads, verge and cill details are itemised in every fixed quote.
Grants: check before you pay full price
Solid-wall homes — most pre-1930s stock — are exactly what current schemes target, with support up to £15,000 for qualifying households. Eligibility depends on EPC band and household circumstances; we advise at survey, free, and handle the paperwork when a scheme applies.
Payback: what EWI actually saves
On a solid-wall semi the Energy Saving Trust puts savings at £300–£500 a year at current prices. Add the avoided cost of separately re-rendering a tired facade (£7,500–£10,000 on the same house) and EWI's effective payback shortens dramatically — it's two projects in one.
Related questions
External wall insulation costs £130–£190 per m² including labour and materials, depending on insulation thickness, system choice and access. Grants of up to £15,000 are available for qualifying homes, and the Energy Saving Trust estimates £300–£500 annual heating savings on a semi-detached property.
EWI fixes 60–150mm of insulation board (EPS, mineral wool or phenolic) to the outside of your walls and renders over the top. On a solid-wall home it typically cuts heating bills by 25–40% — the Energy Saving Trust estimates £300–£500 a year on a semi-detached property.
EWI on a semi-detached property takes about two weeks. Thin-coat silicone rendering is typically completed in a week, and monocouche spray render takes just 3–4 days on a semi-detached house thanks to the efficiency of the spray pump.
Usually not — re-rendering in a similar finish falls under permitted development for most houses. You DO need consent if the property is listed, in a conservation area with an Article 4 direction, or a flat. External wall insulation that changes the appearance may also need approval — we advise on this at survey, free of charge.
Get the exact figure for your home
Free survey, fixed written quote, manufacturer-backed system warranties.