External wall insulation in South Glamorgan
Thinking about external wall insulation anywhere in South Glamorgan? Here is what's involved, what it costs and what the rules in Wales say, with links to every town we cover.
Homes across South Glamorgan
Cardiff's Victorian terraces and conservation areas, inter-war suburbs, and villages across the Vale of Glamorgan.
Your quote will name the certified system, the board thickness and the calculated U-value for your walls, not a vague 'insulation package'.
Services in South Glamorgan
- EWI installation
- EPS insulated render
- Mineral wool EWI
- Phenolic EWI
- Wood fibre EWI
- Brick slip EWI
- Insulated cladding
- Insulating lime render
- Silicone render finish
- Mineral & silicate render
- Pebbledash & dry dash EWI
- Solid wall insulation
- Non-traditional houses
- Bungalow EWI
- Terraced house EWI
- Semi-detached EWI
- Detached house EWI
- Park home insulation
- Flats & low-rise blocks
- Social housing EWI
- EWI for landlords
- EWI repairs
- Failed EWI remediation
- EWI surveys
Towns we cover in South Glamorgan
The rules in Wales
- Planning
- Welsh guidance allows cladding a house without an application if the materials look similar to the original, but external wall insulation that projects more than 16cm from the wall needs planning permission. Any cladding or render in a conservation area, National Park, AONB or World Heritage Site needs permission, listed buildings need consent, and permitted development rights may have been removed by condition or Article 4 direction.
- Building regulations
- Wales has its own Building Regulations and Approved Document L. Renovating a large part of an external wall brings the energy standards into play, so building control approval is needed for EWI.
- Fire safety
- Wales has its own Approved Document B. The system's fire classification, the building's height and the distance to the boundary decide which insulation can be used; on taller residential buildings non-combustible insulation is required.
- Funding
- Warm Homes Nest provides free improvements to low-income owner-occupiers and private tenants, and the Green Homes Wales pilot has offered interest-free loans to households above those thresholds. ECO4 closes on 31 December 2026. These schemes use their own approved installers; our quotes are for privately funded work unless we confirm otherwise in writing. Grants guide
- VAT
- Installing insulation in a home is zero-rated for VAT until 31 March 2027, then 5%.
Checked October 2026. Rules change, so we confirm them for your address at survey.
External wall insulation in South Glamorgan: questions
How much does external wall insulation cost in South Glamorgan?
Guide prices run from about £109 to £175 per square metre for the system and finish, plus scaffolding. For an average home that's about £8,595–£11,695 for a mid-terrace, £13,995–£19,195 for a three-bed semi and £20,495–£28,095 for a four-bed detached house, with VAT at 0% on homes.
How long does external wall insulation take?
It depends on the size of the house and the weather: bungalows usually take one to two weeks on site, terraces two to three, semis three to four and detached houses four to six. Blocks of flats take longer.
Can I stay at home during the work?
Yes. All the work is outside, so you can live at home as normal while the scaffolding is up.
What finishes can I choose?
Silicone or mineral render in many colours, pebbledash, brick slips or cladding, alone or combined.