Internal wall insulation · South Glamorgan
Internal wall insulation in Penarth
From Penarth to Cardiff, we price internal wall insulation after a measured survey — no guesswork, and no work starts until the price is agreed in writing. For terraced homes in Penarth with attractive brick fronts, one approach is to insulate the front internally and the rear externally.
- Free survey in CF64 and nearby
- Guide price from £75 per m² 0% VAT
- Fixed written price before work starts
Free survey in Penarth
Postcode, service and a phone number is all we need.
Part of every quote
- Needs careful detailing at floor joists, reveals and corners
- Keeps the outside of the house exactly as it is
- Loses roughly 50–100mm per insulated wall
- Sockets, radiators, skirting and coving are moved and refitted
What we look for in Penarth
Surveys in Penarth also cover the surrounding CF64 district and towns such as Cardiff and Barry. Penarth is about 3 miles from Cardiff. 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.
Where a property in Penarth is in a conservation area or the front elevation must stay unchanged, internal insulation is often the practical route.
- Postcode district
- CF64
- County or area
- South Glamorgan
- Nation
- Wales
- Nearby
- Cardiff, Barry, Caerphilly, Risca
Planning and building control 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 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 Penarth
| 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
Tell us about the property
Use the quote tool or form, or call. Photos help.
Free survey
We measure, check the walls and confirm approvals.
Fixed written quote
System, details, access, exclusions and VAT in writing.
Installation
Scheduled for suitable weather, with a clear programme.
Internal wall insulation in Penarth: questions
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.
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.
Do you cover Penarth?
Yes — we survey and quote internal wall insulation in Penarth (CF64) and nearby Cardiff, Barry and Caerphilly, with a fixed written price before any work starts.