Internal wall insulation · Wales
Internal wall insulation in Gwent
Internal wall insulation across Gwent: measured survey, clear specification and a fixed written price before any work starts. For terraced homes in Gwent 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 Gwent
Tell us the postcode and what you need.
What you get
- 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
- Loses roughly 50–100mm per insulated wall
- Sockets, radiators, skirting and coving are moved and refitted
Gwent: walls, weather and approvals
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 Gwent: 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.
We plan internal insulation in Gwent homes room by room so you keep the rest of the house usable.
- Nation
- Wales
- Region
- South Wales
- Towns covered
- Newport (Gwent), Cwmbran, Pontypool, Ebbw Vale, Caerphilly, Risca, Abergavenny, Monmouth
- 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 Gwent
| 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
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 Gwent: 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 all of Gwent?
Yes. We survey and quote internal wall insulation across Gwent, including Newport (Gwent), Cwmbran, Pontypool, Ebbw Vale, Caerphilly.
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.