Internal wall insulation · Wales
Internal wall insulation in Mid Glamorgan
Get guide prices online, then a free survey and fixed quote for internal wall insulation in Mid Glamorgan, including Bridgend and Merthyr Tydfil. For terraced homes in Mid Glamorgan with attractive brick fronts, one approach is to insulate the front internally and the rear externally.
- Free survey and fixed written price
- Guide price from £75 per m² 0% VAT
- Planning and building control checked for Wales
Free survey in Mid Glamorgan
Tell us the postcode and what you need.
What you get
- Can be done one room at a time during a renovation
- Loses roughly 50–100mm per insulated wall
- Insulated plasterboard, stud wall or breathable systems
- Sockets, radiators, skirting and coving are moved and refitted
- Keeps the outside of the house exactly as it is

Before we quote in Mid Glamorgan
South Wales has long runs of solid-wall valley terraces, Victorian and Edwardian town housing and post-war council estates.
Parts of Mid Glamorgan 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.
Where a property in Mid Glamorgan is in a conservation area or the front elevation must stay unchanged, internal insulation is often the practical route.
- Nation
- Wales
- Region
- South Wales
- Towns covered
- Rhondda, Bridgend, Merthyr Tydfil, Aberdare, Pontypridd, Maesteg
- Guide price
- From £75 per m² 0% VAT
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.
The Building Regulations as they apply in Wales treat insulating or re-rendering more than half of a wall's area, or more than a quarter of the building's whole envelope, as renovating a thermal element, with Approved Document L (Wales) setting the target. Building control is involved before work starts.
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 Mid Glamorgan
| 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.
From enquiry to finished wall
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 Mid Glamorgan: questions
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.
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.
Do you cover all of Mid Glamorgan?
Yes. We survey and quote internal wall insulation across Mid Glamorgan, including Rhondda, Bridgend, Merthyr Tydfil, Aberdare, Pontypridd.
Do I need planning permission in Wales?
Permitted development rules for houses in Wales are similar to England's: a similar-appearance finish on a house is often permitted, while conservation areas, National Parks, Areas of Outstanding Natural Beauty, flats, commercial buildings and listed buildings need permission or consent. We check your address before quoting.