Cavity insulation for new builds and extensions for Carmarthen properties
If your property is in Carmarthen or the SA31 district or nearby Llanelli and Ammanford, it is within our Dyfed coverage. Carmarthen is one of the main towns we cover in Dyfed.
Carmarthen properties with rendered or painted walls get a closer look at the outer finish, because cracked render can let rain behind it. Where a Carmarthen 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 Dyfed 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.
On compliance, in Carmarthen 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.
What we work from
Your architect's or designer's specification and the energy calculation for the job. We match the product, thickness and fixing to that spec, keep cavities clean as the walls rise, and fit cavity trays, closers and stop ends where shown so the building control inspection goes smoothly.
What is included in Carmarthen
- Clean-cavity working
- Batts or boards to the specified U-value
- Coordination with your bricklayers
- Photo record for building control
Guide prices for Carmarthen
| Cavity insulation for new builds and extensions guide prices | Guide price |
|---|---|
| Full-fill batts supplied and fitted, per m² | £9–£16 |
| Partial-fill boards supplied and fitted, per m² | £14–£26 |
Prices are shown before any VAT; the VAT treatment for new-build work is confirmed on your quote. 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.
How it works in Carmarthen:
Get in touch
Online, by phone or WhatsApp, whichever suits you.
Survey visit
The surveyor checks each wall and looks into the cavity where needed.
Your result in writing
What we found, what it means, and a fixed price if work is needed.
Booked work
Carried out by the installer named on your quote, with their scheme registrations.