External wall insulation · Gwynedd
External wall insulation in Bangor (Gwynedd)
We quote external wall insulation for homes in Bangor (Gwynedd, LL57) and nearby Llangefni and Caernarfon, with guide prices online and a free survey to fix the price. For homes in Bangor (Gwynedd), 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 LL57 and nearby
- Guide price from £105 per m² + scaffold, 0% VAT
- Fixed written price before work starts
Free survey in Bangor (Gwynedd)
Postcode, service and a phone number is all we need.
Part of every quote
- Boards chosen for the wall: EPS, mineral wool, wood fibre or phenolic
- 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
- Typically takes a 225mm solid brick wall from around 2.1 W/m²K to about 0.30 W/m²K with 90–110mm of board

Homes and walls in Bangor (Gwynedd)
We cover Bangor (Gwynedd) and nearby Llangefni, Caernarfon and Llandudno. North Wales has many solid stone and slate-built homes, Victorian seaside terraces and post-war council estates.
Parts of Gwynedd fall in the higher wind-driven rain exposure bands, especially coastal and upland sites, so render specification, movement joints and detailing at cills, verges and the base of the wall matter more than usual.
Whole-house jobs and single elevations are both quoted in Bangor (Gwynedd); a cold gable or rear wall can be done on its own where it suits.
- Postcode district
- LL57
- County or area
- Gwynedd
- Nation
- Wales
- Nearby
- Llangefni, Caernarfon, Llandudno, Colwyn Bay
Approvals in Wales
For homes in Bangor (Gwynedd), the local planning authority decides any borderline cases; changing a brick house to render, or work on flats, usually needs an application in Wales.
Building control in Wales applies to most insulation and re-rendering jobs of this size; the quote states who submits the notice.
What does the survey check before EWI is specified?
- Wall construction and condition, including any damp, cracking or loose render
- Ground levels and the damp-proof course, so the system starts above splash height
- Eaves depth, verges and whether the roofline needs extending
- Window positions, cill depths and reveal space
- Services on the wall: gas, electric meters, flues, soil pipes, satellite dishes and lights
- Planning and Building Regulations position for your property and nation
External wall insulation prices in Bangor (Gwynedd)
| 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.
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.
External wall insulation in Bangor (Gwynedd): 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 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.
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 Bangor (Gwynedd)?
Yes — we survey and quote external wall insulation in Bangor (Gwynedd, LL57) and nearby Llangefni, Caernarfon and Llandudno, with a fixed written price before any work starts.