External wall insulation · Gwynedd
External wall insulation in Llangefni
Homeowners and landlords in Llangefni can get a free survey and a fixed written quote for external wall insulation, covering LL77 and the surrounding area. We plan EWI in Llangefni around the details that cause trouble later — cills, eaves, downpipes and the base of the wall above the damp-proof course.
- Free survey in LL77 and nearby
- Guide price from £105 per m² + scaffold, 0% VAT
- Fixed written price before work starts
Free survey in Llangefni
Postcode, service and a phone number is all we need.
What's included
- Covers tired brick, pebble dash or failing render with a new finish
- Typically takes a 225mm solid brick wall from around 2.1 W/m²K to about 0.30 W/m²K with 90–110mm of board
- Work happens outside, so you can live at home throughout
- Cills, pipes, vents, meter boxes and the roofline detailed as part of the job
Homes and walls in Llangefni
We also cover Bangor (Gwynedd) and Caernarfon, close to Llangefni. Llangefni sits around 8 miles from Bangor (Gwynedd). 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 Llangefni; a cold gable or rear wall can be done on its own where it suits.
- Postcode district
- LL77
- County or area
- Gwynedd
- Nation
- Wales
- Nearby
- Bangor (Gwynedd), Caernarfon, Holyhead, Llandudno
Wales: planning and regulations
For homes in Llangefni, the local planning authority decides any borderline cases; changing a brick house to render, or work on flats, usually needs an application in Wales.
Welsh Building Regulations expect walls to be upgraded when a substantial area is renewed, and building control signs the work off.
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 Llangefni
| 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
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 Llangefni: questions
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.
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.
Do you cover Llangefni?
Yes — we survey and quote external wall insulation in Llangefni (LL77) and nearby Bangor (Gwynedd), Caernarfon and Holyhead, with a fixed written price before any work starts.