Mineral wool EWI · England
Mineral wool external wall insulation in Hertfordshire
Get guide prices online, then a free survey and fixed quote for mineral wool external wall insulation in Hertfordshire, including Stevenage and Hemel Hempstead. On blocks and taller buildings in Hertfordshire, mineral wool is the default because of the fire guidance for external walls.
- Free survey and fixed written price
- Guide price from £125 per m² + scaffold, 0% VAT
- Planning and building control checked for England
Free survey in Hertfordshire
Tell us the postcode and what you need.
Included as standard
- Finished in mineral or silicone render, or brick slip
- Heavier than EPS, so more fixings and careful handling
- Vapour-open, so moisture in solid walls can dry outwards
- Better sound reduction than foam boards
- Used on blocks of flats and buildings with storeys above 11m
Local considerations 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 homes in Hertfordshire near busy roads, mineral wool's sound reduction can be a reason to choose it.
- 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 £125 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.
Combustible materials are banned in the external walls of relevant buildings 18 metres and over (regulation 7(2)), and Approved Document B guidance also covers residential buildings with a storey 11 metres or more above ground. Higher-risk buildings go through the Building Safety Regulator.
What about noise?
Dense mineral wool adds mass and absorbs sound, so homes beside main roads or railways often notice a quieter interior, particularly where windows are also upgraded. The improvement depends on the whole wall and windows, so we don't quote decibel figures without testing.
Mineral wool external wall insulation prices in Hertfordshire
| Item | Guide price | Notes |
|---|---|---|
| Mineral wool + mineral or silicone render | £125–£170 per m²0% VAT | Excluding scaffold |
| Mineral wool + brick slip | £195–£260 per m²0% VAT | Heavier slip systems need extra fixings |
| Three-bed semi, full house | £11,800–£20,2000% VAT | 80–100 m² of wall, including scaffold |
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.
Mineral wool EWI in Hertfordshire: questions
Can mineral wool EWI have a brick finish?
Yes. Brick slips can be bonded over mineral wool systems designed for them, with additional fixings for the extra weight.
Is mineral wool needed for a bungalow?
Rarely for fire reasons. It may still be chosen on a damp-prone solid wall where a vapour-open build-up is wanted.
Is mineral wool better than EPS?
Not always better — different. Mineral wool wins on fire performance, breathability and acoustics; EPS wins on cost, weight and thinner boards for the same U-value. The wall, the building height and your priorities decide it.
Do you cover all of Hertfordshire?
Yes. We survey and quote mineral wool external 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.