External wall insulation · Somerset
External wall insulation in Portishead
Looking for external wall insulation in Portishead? We survey homes across Portishead and the BS20 area, then give you a fixed written price before any work starts. For homes in Portishead, the survey starts with the wall itself: solid brick, stone or concrete, and whether any old render is sound enough to insulate over.
- Free survey in BS20 and nearby
- Guide price from £105 per m² + scaffold, 0% VAT
- Fixed written price before work starts
Free survey in Portishead
Postcode, service and a phone number is all we need.
What you get
- Cills, pipes, vents, meter boxes and the roofline detailed as part of the job
- Work happens outside, so you can live at home throughout
- Typically takes a 225mm solid brick wall from around 2.1 W/m²K to about 0.30 W/m²K with 90–110mm of board
- Covers tired brick, pebble dash or failing render with a new finish
Homes and walls in Portishead
We also cover Nailsea and Clevedon, close to Portishead. Portishead is about 19 miles from Bath. The South West has many stone and solid-walled cottages, exposed coastal properties and a share of post-war system-built houses, including types such as the Cornish Unit.
Exposure to wind-driven rain varies across Somerset: 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 Portishead around the details that cause trouble later — cills, eaves, downpipes and the base of the wall above the damp-proof course.
- Postcode district
- BS20
- County or area
- Somerset
- Nation
- England
- Nearby
- Nailsea, Clevedon, Kingswood, Mangotsfield
Approvals in England
For a house in Portishead, external insulation or render is often permitted development if it looks similar to the existing walls; conservation areas, flats, commercial buildings and listed buildings need permission or consent, so we check your address first.
If the work covers more than half of a wall, or a quarter of the building's whole envelope, it counts as renovating a thermal element, with a target of about 0.30 W/m²K where 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 Portishead
| 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 Portishead: 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.
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.
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.
Do you cover Portishead?
Yes — we survey and quote external wall insulation in Portishead (BS20) and nearby Nailsea, Clevedon and Kingswood, with a fixed written price before any work starts.