Mineral wool EWI · Gwynedd
Mineral wool external wall insulation in Llangefni
From Llangefni to Bangor (Gwynedd), we price mineral wool external wall insulation after a measured survey — no guesswork, and no work starts until the price is agreed in writing. Older solid-walled homes in Llangefni can suit a vapour-open mineral wool build-up better than foam; the survey checks the wall first.
- Free survey in LL77 and nearby
- Guide price from £125 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
- Better sound reduction than foam boards
- Heavier than EPS, so more fixings and careful handling
- Used on blocks of flats and buildings with storeys above 11m
- Finished in mineral or silicone render, or brick slip
Homes and walls in Llangefni
As well as Llangefni itself, we quote in Bangor (Gwynedd), Caernarfon and Holyhead. It's roughly 8 miles from Llangefni to Bangor (Gwynedd), the largest town in 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.
For homes in Llangefni near busy roads, mineral wool's sound reduction can be a reason to choose it.
- 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.
Wales applies its own external wall fire rules, updated in 2025; on taller residential buildings we specify non-combustible mineral wool systems.
What about noise?
Dense mineral wool adds mass and absorbs sound, so homes beside main roads or railways often notice a quieter interior, particularly where windows are also upgraded. The improvement depends on the whole wall and windows, so we don't quote decibel figures without testing.
Mineral wool external wall insulation prices in Llangefni
| Item | Guide price | Notes |
|---|---|---|
| Mineral wool + mineral or silicone render | £125–£170 per m²0% VAT | Excluding scaffold |
| Mineral wool + brick slip | £195–£260 per m²0% VAT | Heavier slip systems need extra fixings |
| Three-bed semi, full house | £11,800–£20,2000% VAT | 80–100 m² of wall, including scaffold |
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
Get a guide price
Try the online quote tool for a ballpark figure.
Book the survey
A visit at a time that suits you.
Agree the quote
Nothing starts until you've signed the written price.
We do the work
Planned around weather, with you kept informed.
Mineral wool EWI in Llangefni: questions
Can mineral wool EWI have a brick finish?
Yes. Brick slips can be bonded over mineral wool systems designed for them, with additional fixings for the extra weight.
Does mineral wool get wet?
It is water-repellent and protected by the render system. Like any insulation it must not be left exposed to rain during installation, so boards are covered and work stops in wet weather.
Is mineral wool needed for a bungalow?
Rarely for fire reasons. It may still be chosen on a damp-prone solid wall where a vapour-open build-up is wanted.
Do you cover Llangefni?
Yes — we survey and quote mineral wool external wall insulation in Llangefni (LL77) and nearby Bangor (Gwynedd), Caernarfon and Holyhead, with a fixed written price before any work starts.