Solid wall insulation · England
Solid wall insulation in Cornwall
Planning solid wall insulation anywhere in Cornwall? We cover towns including Redruth and Falmouth, and check planning and building control for each address. For Cornwall homeowners weighing external against internal insulation, the survey sets out both with prices.
- Free survey and fixed written price
- Guide price from £75 per m² + scaffold, 0% VAT
- Planning and building control checked for England
Free survey in Cornwall
Tell us the postcode and what you need.
What's included
- Solid walls can lose heat roughly twice as fast as an insulated cavity wall
- In England and Wales, Building Regulations apply when more than half of a wall is treated
- Internal insulation suits single rooms or where the outside can't change
- External insulation keeps room sizes and treats cold bridges well
- Breathable options for stone and lime-mortared walls
Homes and walls in Cornwall
The South West has many stone and solid-walled cottages, exposed coastal properties and a share of post-war system-built houses, including types such as the Cornish Unit.
Parts of Cornwall fall in the higher wind-driven rain exposure bands, especially coastal and upland sites, so render specification, movement joints and detailing at cills, verges and the base of the wall matter more than usual.
On solid-walled houses in Cornwall, the gable or the most weather-exposed wall is often the place to start.
- Nation
- England
- Region
- South West
- Towns covered
- Redruth, Falmouth, St Austell, Truro, Camborne, Penzance, Newquay, Bodmin
- Guide price
- From £75 per m² + scaffold · 0% VAT
Approvals in England
For houses, external wall insulation and render are often permitted development where the finish looks similar to the existing walls. Planning permission is usually needed in conservation areas, National Parks, National Landscapes, the Broads and World Heritage Sites (where cladding a house in stone, artificial stone, pebble dash, render, timber, plastic or tiles isn't permitted development), for flats and maisonettes, for commercial buildings, under an Article 4 direction, or where the look changes noticeably. Listed buildings need listed building consent.
Renovating more than half of a wall's area — insulating it, or stripping and re-rendering it — or more than a quarter of the building's whole external envelope brings in the energy requirements of Part L, so building control needs to be involved and the wall should reach about 0.30 W/m²K where that's technically, functionally and economically feasible.
How can I tell if my walls are solid?
Measure the wall thickness at a window or door: about 225mm (9 inches) of brick usually means solid, while 260mm or more often means a cavity. On exposed brick, a pattern with bricks laid end-on (headers) every few courses points to solid construction. Stone walls are usually solid regardless of thickness. Age is a strong clue too — most homes built before the 1920s are solid-walled.
Solid wall insulation prices in Cornwall
| Item | Guide price | Notes |
|---|---|---|
| External (EWI) | £105–£210 per m²0% VAT | By board and finish |
| Internal (IWI) | £75–£130 per m²0% VAT | Plus making good |
| Survey and written recommendation | Free with a quote |
Confirmed by a fixed written quote after survey. 0% VAT: installing insulation in a home is zero-rated until 31 March 2027, so these figures are the total; 5% applies from 1 April 2027.
From enquiry to finished wall
Enquiry
Send your postcode and a few details.
Measured survey
Walls, damp, eaves, cills and services recorded.
Written price
A fixed price with the specification attached.
Work and handover
Installed, inspected and documents handed over.
Solid wall insulation in Cornwall: questions
Is solid wall insulation worth it?
For many solid-walled homes it's one of the biggest single improvements to comfort, because the walls are often the largest heat-loss area. Savings depend on the home and heating, so we don't promise a figure.
Can I do one wall at a time?
Yes. Many owners start with the coldest or most exposed elevation, often a gable end.
Can I get a grant for solid wall insulation?
Some schemes cover it for eligible households — for example ECO4 until 31 December 2026, Home Energy Scotland's grant and loan, Wales' Warm Homes Nest and NI's Affordable Warmth Scheme. Each has its own eligibility and installer rules; see our grants guide.
Do you cover all of Cornwall?
Yes. We survey and quote solid wall insulation across Cornwall, including Redruth, Falmouth, St Austell, Truro, Camborne.
Do I need planning permission in England?
For houses, external wall insulation and render are often permitted development where the finish looks similar to the existing walls. We check your address before quoting.