Internal wall insulation · South Glamorgan
Internal wall insulation in Cardiff
Looking for internal wall insulation in Cardiff? We survey homes across Cardiff and the CF10 area, then give you a fixed written price before any work starts. Where a property in Cardiff is in a conservation area or the front elevation must stay unchanged, internal insulation is often the practical route.
- Free survey in CF10 and nearby
- Guide price from £75 per m² 0% VAT
- Fixed written price before work starts
Free survey in Cardiff
Postcode, service and a phone number is all we need.
What's included
- Can be done one room at a time during a renovation
- Insulated plasterboard, stud wall or breathable systems
- Keeps the outside of the house exactly as it is
- Needs careful detailing at floor joists, reveals and corners
Local considerations in Cardiff
As well as Cardiff itself, we quote in Penarth, Caerphilly and Barry. South Wales has long runs of solid-wall valley terraces, Victorian and Edwardian town housing and post-war council estates.
Exposure to wind-driven rain varies across South Glamorgan: sheltered town streets fare better than walls on high ground or facing the prevailing weather, and the render, beads and cill details are chosen with that in mind.
For terraced homes in Cardiff with attractive brick fronts, one approach is to insulate the front internally and the rear externally.
- Postcode district
- CF10
- County or area
- South Glamorgan
- Nation
- Wales
- Nearby
- Penarth, Caerphilly, Barry, Risca
Wales: planning and regulations
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 Cardiff
| 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
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.
Internal wall insulation in Cardiff: questions
How much room space will I lose?
Usually 50–100mm on each insulated wall, depending on the system.
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.
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.
Do you cover Cardiff?
Yes — we survey and quote internal wall insulation in Cardiff (CF10) and nearby Penarth, Caerphilly and Barry, with a fixed written price before any work starts.