Who we help · Houses
Non-traditional / system-built (PRC, Airey, Cornish, Wimpey No-Fines, BISF, timber frame)
Usual measures: EWI (often the only route), loft, floor. Watch-out: Structural survey; some PRC types need repair to be mortgageable.
Typical prices
Semi / end-terrace prices
- External wall insulation + render£14,000–£24,000
- Loft insulation (new or top-up)£600–£1,300
- Suspended floor insulation£1,500–£4,500
Before grants · updated 11 October 2026 · a survey confirms the final figure.
Read the full guide: Non-traditional homes
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Construction, heat loss and watch-outs
- Typical construction
- Concrete panels, no-fines concrete, steel or timber frame
- Where heat is lost
- Thin uninsulated walls
- Usual measures
- EWI (often the only route), loft, floor
- Watch-outs
- Structural survey; some PRC types need repair to be mortgageable
Structural survey first
Some PRC types need a recognised repair to be mortgageable. We survey the structure before any insulation goes on, and EWI is often the only route for the walls.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.
Loft insulation
Mineral wool laid between and across the joists to 270–300 mm so heat stays in the rooms below.
Suspended timber floor insulation
Mineral wool or rigid board between the joists with an airtight membrane.
Solid floor insulation
PIR or XPS boards over the slab with a new screed or floating floor.
Timber frame walls
Mineral wool or wood-fibre between the studs with a vapour control layer.
Prices
Semi / end-terrace price column
| Measure | Semi / end-terrace |
|---|---|
| Loft insulation (new or top-up) | £600–£1,300 |
| Loft clearance and replacement | £1,500–£3,000 |
| Room-in-roof | £4,000–£9,000 |
| Cavity wall insulation | £1,200–£2,500 |
| Cavity extraction and refill | £3,500–£7,500 |
| Internal wall insulation (whole home) | £10,000–£20,000 |
| External wall insulation + render | £14,000–£24,000 |
| EWI with brick slip finish | £18,000–£32,000 |
| Re-render only (K Rend silicone) | £6,500–£12,000 |
| Suspended floor insulation | £1,500–£4,500 |
| Draught-proofing | £300–£800 |
| Whole-house fabric package | £22,000–£45,000 |
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.Houses
Other property types
- Detached house
- Semi-detached house
- End-of-terrace
- Mid-terrace
- Townhouse
- Mews house and cottage
- Detached bungalow
- Semi and terraced bungalow
- Chalet and dormer bungalow
- Period home
- 1930s home
- Post-war and ex-council house
- Listed building or conservation area
- Farmhouse, barn conversion or rural home
- New build or self-build
- Park and mobile home
- Every property type
Begin your project
Price insulation for your non-traditional / system-built
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.