External wall insulation · England
External wall insulation in Hampshire
Planning external wall insulation anywhere in Hampshire? We cover towns including Southampton and Portsmouth, and check planning and building control for each address. We plan EWI in Hampshire around the details that cause trouble later — cills, eaves, downpipes and the base of the wall above the damp-proof course.
- Free survey and fixed written price
- Guide price from £105 per m² + scaffold, 0% VAT
- Planning and building control checked for England
Free survey in Hampshire
Tell us the postcode and what you need.
What the job covers
- Typically takes a 225mm solid brick wall from around 2.1 W/m²K to about 0.30 W/m²K with 90–110mm of board
- Boards chosen for the wall: EPS, mineral wool, wood fibre or phenolic
- Work happens outside, so you can live at home throughout
- Cills, pipes, vents, meter boxes and the roofline detailed as part of the job
- Installing wall insulation in homes is currently zero-rated for VAT until 31 March 2027
Before we quote in Hampshire
Homes across the South East range from inter-war semis and post-war estates, which are mostly cavity-walled, to older solid-walled cottages and Victorian town terraces.
Exposure to wind-driven rain varies across Hampshire: sheltered town streets fare better than walls on high ground or facing the prevailing weather, and the render, beads and cill details are chosen with that in mind.
We plan EWI in Hampshire around the details that cause trouble later — cills, eaves, downpipes and the base of the wall above the damp-proof course.
- Nation
- England
- Region
- South East
- Towns covered
- Southampton, Portsmouth, Basingstoke, Gosport, Waterlooville, Aldershot, Farnborough, Fareham…
- Guide price
- From £105 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 does external wall insulation work?
Heat moves out through a wall faster when the wall is solid or poorly insulated. EWI wraps the outside face in a continuous layer of insulation, so the masonry stays on the warm side and the cold bridges at floor and party-wall junctions are reduced. The boards are bonded with adhesive and, on most walls, mechanically fixed. A base coat with an embedded glass-fibre mesh goes over the top, then a primer and the decorative finish.
Because the wall itself sits inside the insulation, it stays warmer and drier, and the rooms keep their full size. That is the main difference from internal insulation.
External wall insulation prices in Hampshire
| Item | Guide price | Notes |
|---|---|---|
| EPS system with silicone render | £105–£145 per m²0% VAT | Most common choice for houses |
| Mineral wool system | £125–£170 per m²0% VAT | Non-combustible, vapour-open |
| Brick-slip finish over insulation | £185–£260 per m²0% VAT | Where a brick look is wanted |
| Three-bed semi, EPS + silicone (incl. scaffold) | £10,200–£17,7000% VAT | 80–100 m² of wall; depends on detailing and access |
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.
How it works
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.
External wall insulation in Hampshire: questions
Does EWI need Building Regulations approval?
In England and Wales, usually. Insulating more than half of a wall's area, or more than a quarter of the building's whole external envelope, counts as renovating a thermal element, so building control needs to be involved and the wall should reach about 0.30 W/m²K where that's practical. Scotland and Northern Ireland have their own building standards processes.
Does external wall insulation cause damp?
Not when it is specified and detailed properly. Problems usually come from poor detailing: no starter track above the damp-proof course, gaps at cills and penetrations, or a vapour-closed system on a wall that needs to breathe. The survey checks moisture, ground levels and the wall type before a system is chosen.
How long does external wall insulation last?
A well-installed render system is commonly expected to last 25–30 years or more, with occasional cleaning and inspection of sealants. The system manufacturer's documentation states the expected service life for the specific build-up.
Do you cover all of Hampshire?
Yes. We survey and quote external wall insulation across Hampshire, including Southampton, Portsmouth, Basingstoke, Gosport, Waterlooville.
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.