Internal wall insulation · Gwynedd
Internal wall insulation in Llangefni
We quote internal wall insulation for homes in Llangefni (LL77) and nearby Bangor (Gwynedd) and Caernarfon, with guide prices online and a free survey to fix the price. For terraced homes in Llangefni with attractive brick fronts, one approach is to insulate the front internally and the rear externally.
- Free survey in LL77 and nearby
- Guide price from £75 per m² 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
- Keeps the outside of the house exactly as it is
- Loses roughly 50–100mm per insulated wall
- Can be done one room at a time during a renovation
- Needs careful detailing at floor joists, reveals and corners
Local considerations in Llangefni
We also cover Bangor (Gwynedd) and Caernarfon, close to Llangefni. Llangefni is about 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.
We plan internal insulation in Llangefni homes room by room so you keep the rest of the house usable.
- Postcode district
- LL77
- County or area
- Gwynedd
- Nation
- Wales
- Nearby
- Bangor (Gwynedd), Caernarfon, Holyhead, Llandudno
Permissions in Wales
Internal insulation rarely needs planning permission, but in England and Wales insulating or replastering more than half of a wall's area involves building control, and listed buildings need consent for internal changes that affect their character.
What are the options for internal insulation?
- Insulated plasterboard — PIR or phenolic foam bonded to plasterboard, fixed to the wall and skimmed. Thinnest option.
- Insulated stud wall — a timber or metal frame filled with insulation, with a vapour control layer and plasterboard. Takes more space but runs services easily.
- Wood fibre and lime — breathable boards finished in lime plaster, for older walls that need to manage moisture.
Internal wall insulation prices in Llangefni
| Item | Guide price | Notes |
|---|---|---|
| Insulated plasterboard, supplied and skimmed | £75–£110 per m²0% VAT | |
| Insulated stud wall | £90–£130 per m²0% VAT | |
| Typical bedroom, one external wall | £1,795–£2,9950% VAT | Including making good |
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
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.
Internal wall insulation in Llangefni: questions
How much room space will I lose?
Usually 50–100mm on each insulated wall, depending on the system.
Can I stay in the house?
Yes, but each room is out of use while it's worked on, typically 3–5 days.
Is internal insulation cheaper than external?
Per m² usually yes, but the cost of moving fittings and redecorating narrows the gap on whole-house jobs.
Do you cover Llangefni?
Yes — we survey and quote internal wall insulation in Llangefni (LL77) and nearby Bangor (Gwynedd), Caernarfon and Holyhead, with a fixed written price before any work starts.