Cost guide
How much does external wall insulation cost?
External wall insulation costs £100 to £160 per square metre including scaffold. A typical three bedroom semi runs £10,000 to £18,000. ECO4 grant funding may cover most of it for eligible households, and grant work must be PAS 2030 certified.
Typical prices
Ranges, not quotes. A quote depends on your room.
| Work | Typical UK price |
|---|---|
| EPS insulation and render, per m² | £100 to £135 |
| Mineral wool insulation and render, per m² | £120 to £160 |
| Typical three bedroom semi | £10,000 to £18,000 |
| Typical mid-terrace, rear and front | £7,000 to £13,000 |
| Scaffold, included above | £1,200 to £2,500 |
Check the installer is PAS 2030 certified and TrustMark registered if any grant money is involved, because without both the funding does not apply and the guarantee does not exist.
What moves the price
- Insulation thickness and type. Mineral wool costs more than EPS and is used where fire performance matters.
- How much has to move. Sills, soffits, downpipes, flues and meter boxes all need extending or relocating.
- Scaffold for the full elevation, which on EWI is never a partial job.
- The topcoat system, the same range of choices as any thin-coat render.
- Whether it is grant funded, which brings PAS 2030 certification, TrustMark registration and a survey into the price.
What the money buys: fixing eps or mineral wool board to a solid wall and rendering over it.
Who quotes for it
Questions about external wall insulation
Does it cause damp?
Done properly it reduces it, because it puts the dew point outside the masonry and keeps the wall warm. Done badly, with a waterproof system on a wall that is already wet or with a bad detail at the damp proof course, it traps water. The detailing is the whole question.
Do I need planning permission?
Usually not, but more often than for plain render: it changes the external appearance and thickness. Listed buildings and conservation areas almost always need consent, and some estates have covenants. Ask the council first.