Cavity wall insulation for Caerphilly properties
Our Gwent coverage takes in Caerphilly (CF83) and nearby Risca, Newport and Cwmbran. It is about 9 miles west of Newport.
Caerphilly properties with rendered or painted walls get a closer look at the outer finish, because cracked render can let rain behind it. Where a Caerphilly property has an extension or a conservatory, we check how the old and new walls meet, because that junction is often missed.
Every elevation is judged on its own exposure. Parts of Gwent face some of the heaviest wind-driven rain in the UK, especially exposed coastal and upland sites. Here the survey is stricter: some walls suit only certain certified systems, and some should not be filled at all.
For regulations, in Caerphilly filling a cavity is notifiable work under the Building Regulations as they apply in Wales, usually self-certified through a competent person scheme.
Funding in Wales
In Wales, Warm Homes Nest offers free improvements to eligible low-income households, and ECO4 runs to 31 December 2026.
Sources: Welsh Government: warmer and more energy efficient homes (July 2026); GOV.UK: extending the ECO4 end date, government response.
Is my wall suitable for cavity wall insulation?
Most homes built from the 1920s onwards have cavity walls, but having a cavity is not the same as being suitable. The Energy Saving Trust's rule of thumb is a cavity of at least 50mm, clear of rubble, behind masonry in good condition, on a wall that is not exposed to severe driving rain or flood risk.
What is included in Caerphilly
- Borescope check where the cavity is in doubt
- Certified mineral wool or bonded bead system
- Suitability survey with photos and a written result
- Cavity barriers at party walls
Guide prices for Caerphilly
| Cavity wall insulation guide prices | Guide price |
|---|---|
| Detached house | £2,295–£3,795 |
| Semi-detached house | £1,495–£2,495 |
| End-terrace house | £1,295–£2,195 |
| Detached bungalow | £1,295–£2,195 |
| Semi-detached bungalow | £895–£1,595 |
| Mid-terrace house | £795–£1,395 |
No VAT is charged on installing insulation in homes until 31 March 2027 (then 5%). Guide ranges only: the fixed price is confirmed in writing before any work starts, and anything that could not be seen at survey is agreed with you first.
What happens next for a Caerphilly property:
Tell us about the property
Postcode, property type and what you need.
Free survey
Walls, cavity, condition and exposure checked and photographed.
Written result and price
Suitable, suitable after repairs, or not suitable, with a fixed price.
Work and paperwork
Installation, making good, and the regulations and guarantee paperwork.