Solid wall insulation · England
Solid wall insulation in Hertfordshire
Get guide prices online, then a free survey and fixed quote for solid wall insulation in Hertfordshire, including Stevenage and Hemel Hempstead. On solid-walled houses in Hertfordshire, the gable or the most weather-exposed wall is often the place to start.
- 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 Hertfordshire
Tell us the postcode and what you need.
What you get
- 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
- Both can be done in stages, elevation by elevation or room by room
Before we quote in Hertfordshire
The East of England has a mix of post-war estates, inter-war semis and older solid brick and flint cottages, with some system-built council homes on post-war estates.
Much of Hertfordshire sits in the lower wind-driven rain exposure bands, which keeps the choice of finishes wide — though hilltop, coastal and exposed gable walls can still need a tougher specification, so we check the actual site.
For Hertfordshire homeowners weighing external against internal insulation, the survey sets out both with prices.
- Nation
- England
- Region
- East of England
- Towns covered
- Watford, Stevenage, Hemel Hempstead, St Albans, Welwyn Garden City, Cheshunt, Letchworth Garden City, Hatfield…
- Guide price
- From £75 per m² + scaffold · 0% VAT
England: planning and regulations
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 Hertfordshire
| 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.
What happens next
Tell us about the property
Use the quote tool or form, or call. Photos help.
Free survey
We measure, check the walls and confirm approvals.
Fixed written quote
System, details, access, exclusions and VAT in writing.
Installation
Scheduled for suitable weather, with a clear programme.
Solid wall insulation in Hertfordshire: questions
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.
Can I do one wall at a time?
Yes. Many owners start with the coldest or most exposed elevation, often a gable end.
Does solid wall insulation cause condensation?
It can if detailed poorly, particularly internally. A condensation risk check for the proposed build-up and careful detailing at joists, reveals and corners avoid it.
Do you cover all of Hertfordshire?
Yes. We survey and quote solid wall insulation across Hertfordshire, including Watford, Stevenage, Hemel Hempstead, St Albans, Welwyn Garden City.
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.