Who we help · Flats and blocks of flats
Ex-local-authority flat or maisonette
Usual measures: Whole-block EWI, roof, windows. Watch-out: Works usually via council or freeholder.
Typical prices
Flat / block prices
- External wall insulation + render£130–£220 per m²block
- Internal wall insulation (whole home)£5,000–£10,000
- Draught-proofing£200–£500
Before grants · updated 11 October 2026 · a survey confirms the final figure.
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Construction, heat loss and watch-outs
- Typical construction
- Concrete, cavity, system-built
- Where heat is lost
- Walls, roof, windows
- Usual measures
- Whole-block EWI, roof, windows
- Watch-outs
- Works usually via council or freeholder
Leaseholders and freeholders
Work inside your flat is usually yours to arrange, but check your lease. The roof, loft, external walls and windows are normally the freeholder's, so those need their consent — and EWI is only ever done as a whole-block project.Recommended
The insulation we usually recommend
External wall insulation (EWI)
A complete certified build-up of insulation board, mesh and render from one system holder.
Internal wall insulation (IWI)
Insulated plasterboard or stud systems fitted inside solid walls where the outside must not change.
Draught-proofing
Sealing doors, windows, letterboxes, hatches, floorboards and unused chimneys — every home's quick win.
Prices
Flat / block price column
| Measure | Flat / block |
|---|---|
| Loft insulation (new or top-up) | £400–£900top floor |
| Loft clearance and replacement | £900–£2,000 |
| Room-in-roof | £3,000–£6,000 |
| Cavity wall insulation | £600–£1,200 per flatper flat |
| Cavity extraction and refill | Block survey |
| Internal wall insulation (whole home) | £5,000–£10,000 |
| External wall insulation + render | £130–£220 per m²block |
| EWI with brick slip finish | £170–£280 per m² |
| Re-render only (K Rend silicone) | £55–£95 per m² |
| Suspended floor insulation | £1,200–£3,000ground floor |
| Draught-proofing | £200–£500 |
| Whole-house fabric package | Per-block quote |
Indicative ranges for London and the South East, supplied and installed, including VAT, before grants. Updated 11 October 2026. A survey confirms your final price.
Grants and savings that may help
- ECO4Closes in 73 days
Up to fully funded; paid by energy suppliers per measure
Grant via local councils (£960m nationally in 2026/27)
- Social Housing Fund
Landlord-led bids
Saves 20% VAT
- Local schemes
Varies
Eligibility depends on your circumstances and is confirmed by evidence and the funder or council.
0% VAT on energy-saving materials
Insulation, solar panels, batteries and heat pumps installed in homes in Great Britain are zero-rated for VAT until 31 March 2027. Windows and doors are not included.Flats and blocks of flats
Other property types
Begin your project
Price insulation for your ex-local-authority flat or maisonette
See a price range for your property type in two minutes, with grants and 0% VAT applied where they fit. A survey always confirms the final figure.