Internal wall insulation · England
Internal wall insulation in Hertfordshire
We provide internal wall insulation across Hertfordshire, including Watford, Stevenage and Hemel Hempstead, with a free survey and fixed written price. For terraced homes in Hertfordshire with attractive brick fronts, one approach is to insulate the front internally and the rear externally.
- Free survey and fixed written price
- Guide price from £75 per m² 0% VAT
- Planning and building control checked for England
Free survey in Hertfordshire
Tell us the postcode and what you need.
What you get
- Keeps the outside of the house exactly as it is
- Can be done one room at a time during a renovation
- Insulated plasterboard, stud wall or breathable systems
- Loses roughly 50–100mm per insulated wall
- Sockets, radiators, skirting and coving are moved and refitted
What we look for 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.
We plan internal insulation in Hertfordshire homes room by room so you keep the rest of the house usable.
- 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 0% VAT
Approvals in England
Internal insulation rarely needs planning permission, but in England and Wales insulating or replastering more than half of a wall's area involves building control, and listed buildings need consent for internal changes that affect their character.
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.
What are the risks with internal insulation?
Insulating inside makes the masonry colder, so moisture risk rises. Weak points are where floor joists bear into the wall, window reveals and corners. A condensation risk check for the build-up, a continuous vapour control layer where specified, and returning insulation into reveals deal with most of it.
Internal wall insulation prices in Hertfordshire
| Item | Guide price | Notes |
|---|---|---|
| Insulated plasterboard, supplied and skimmed | £75–£110 per m²0% VAT | |
| Insulated stud wall | £90–£130 per m²0% VAT | |
| Typical bedroom, one external wall | £1,795–£2,9950% VAT | Including making good |
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
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.
Internal wall insulation in Hertfordshire: questions
Can I stay in the house?
Yes, but each room is out of use while it's worked on, typically 3–5 days.
What happens to my radiators and sockets?
They're taken off and refitted on the new wall face. Electrical work is done by a qualified electrician.
Is internal insulation cheaper than external?
Per m² usually yes, but the cost of moving fittings and redecorating narrows the gap on whole-house jobs.
Do you cover all of Hertfordshire?
Yes. We survey and quote internal 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.