Who we help · Houses
Listed building or conservation area
Usual measures: Breathable IWI, thermal lime render, secondary glazing, loft, floor. Watch-out: Listed building consent; Article 4; no EWI on fronts without planning.
Typical prices
Semi / end-terrace prices
- Internal wall insulation (whole home)£10,000–£20,000
- 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: Listed buildings and conservation areas
Open the guideAt a glance
Construction, heat loss and watch-outs
- Typical construction
- Historic fabric
- Where heat is lost
- Walls, windows, roof
- Usual measures
- Breathable IWI, thermal lime render, secondary glazing, loft, floor
- Watch-outs
- Listed building consent; Article 4; no EWI on fronts without planning
Consents and breathable materials
Listed buildings need listed building consent, conservation areas and Article 4 directions can restrict changes to the outside, and solid walls need breathable materials after a moisture risk check.Recommended
The insulation we usually recommend
Breathable IWI for period homes
Wood-fibre, cork or hemp-lime systems that let solid walls stay dry.
Insulating (thermal) lime render
Lime render with an insulating aggregate for modest U-value gains on old walls.
Lime render
Breathable lime render and lime plaster for older solid walls.
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.
Sheep's wool insulation
Natural insulation that handles moisture, popular with period owners.
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
- Non-traditional / system-built
- 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 listed building or conservation area
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.