Internal wall insulation · Gwynedd
Internal wall insulation in Caernarfon
Looking for internal wall insulation in Caernarfon? We survey homes across Caernarfon and the LL55 area, then give you a fixed written price before any work starts. Where a property in Caernarfon is in a conservation area or the front elevation must stay unchanged, internal insulation is often the practical route.
- Free survey in LL55 and nearby
- Guide price from £75 per m² 0% VAT
- Fixed written price before work starts
Free survey in Caernarfon
Postcode, service and a phone number is all we need.
What's included
- Keeps the outside of the house exactly as it is
- Can be done one room at a time during a renovation
- Needs careful detailing at floor joists, reveals and corners
- Sockets, radiators, skirting and coving are moved and refitted
Local considerations in Caernarfon
As well as Caernarfon itself, we quote in Llangefni, Bangor (Gwynedd) and Holyhead. Caernarfon 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 Caernarfon homes room by room so you keep the rest of the house usable.
- Postcode district
- LL55
- County or area
- Gwynedd
- Nation
- Wales
- Nearby
- Llangefni, Bangor (Gwynedd), Holyhead, Llandudno
Permissions in Wales
Planning isn't usually involved with internal insulation. Building control is, once more than half of a wall is treated, and listed buildings need listed building consent.
What are the risks with internal insulation?
Insulating inside makes the masonry colder, so moisture risk rises. Weak points are where floor joists bear into the wall, window reveals and corners. A condensation risk check for the build-up, a continuous vapour control layer where specified, and returning insulation into reveals deal with most of it.
Internal wall insulation prices in Caernarfon
| 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.
What happens next
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 Caernarfon: questions
Can I stay in the house?
Yes, but each room is out of use while it's worked on, typically 3–5 days.
What happens to my radiators and sockets?
They're taken off and refitted on the new wall face. Electrical work is done by a qualified electrician.
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 Caernarfon?
Yes — we survey and quote internal wall insulation in Caernarfon (LL55) and nearby Llangefni, Bangor (Gwynedd) and Holyhead, with a fixed written price before any work starts.