External wall insulation · Greater London
External wall insulation in Carshalton
From Carshalton to Wallington, we price external wall insulation after a measured survey — no guesswork, and no work starts until the price is agreed in writing. We plan EWI in Carshalton around the details that cause trouble later — cills, eaves, downpipes and the base of the wall above the damp-proof course.
- Free survey in SM5 and nearby
- Guide price from £105 per m² + scaffold, 0% VAT
- Fixed written price before work starts
Free survey in Carshalton
Postcode, service and a phone number is all we need.
What's included
- 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
- Covers tired brick, pebble dash or failing render with a new finish
What we look for in Carshalton
We also cover Wallington and Sutton, close to Carshalton. London's housing includes a large stock of Victorian and Edwardian solid-wall terraces, inter-war semis and post-war blocks, and conservation areas cover many streets — so planning is often the first question for external work.
Much of Greater London 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 Carshalton, the survey starts with the wall itself: solid brick, stone or concrete, and whether any old render is sound enough to insulate over.
- Postcode district
- SM5
- County or area
- Greater London
- Nation
- England
- Nearby
- Wallington, Sutton, Mitcham, Morden
England: planning and regulations
Before quoting in Carshalton, we check whether the property is in a conservation area, under an Article 4 direction or listed, because that decides whether changing the outside needs planning permission.
Insulating or re-rendering more than half of a wall's area brings in Part L of the Building Regulations, so building control is notified and the wall is upgraded to about 0.30 W/m²K where practical.
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 Carshalton
| 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.
From enquiry to finished wall
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 Carshalton: questions
Can EWI go over pebble dash?
Usually yes. The dash is tested for adhesion and hollow areas; sound dash can be insulated over with additional mechanical fixings, while loose areas are removed first.
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.
How much does external wall insulation cost?
Our guide price for EWI is £105–£170 per m² of wall depending on the system, plus scaffolding. A typical three-bed semi with EPS and silicone render comes to roughly £10,200–£17,700 for the whole house, including scaffold. Installing insulation in a home is zero-rated for VAT until 31 March 2027, so that's the total. You get a fixed written price after a free survey.
Do you cover Carshalton?
Yes — we survey and quote external wall insulation in Carshalton (SM5) and nearby Wallington, Sutton and Mitcham, with a fixed written price before any work starts.