Bonded polystyrene bead insulation for Caernarfon properties
Our Gwynedd coverage takes in Caernarfon (LL55) and nearby Bangor, Porthmadog and Holyhead. It is around 6 miles south-west of Bangor.
For semi-detached and terraced homes in Caernarfon, cavity barriers are fitted where your wall meets your neighbour's so the fill stays on your side. Most Caernarfon houses built from the 1920s onwards have cavity walls, but the survey still checks each one: cavity width, debris, the condition of the brickwork and how exposed each wall is.
Every elevation is judged on its own exposure. Parts of Gwynedd 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 Caernarfon 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.
Where bonded beads make sense
Beads behave a little like a liquid as they go in, so they fill narrow and irregular cavities more evenly than fibre. The binder stops them pouring out if a brick is removed later. Some certified bead systems are approved for higher driving-rain exposure than fibre systems, which is why they are common on western and coastal elevations.
What is included in Caernarfon
- Making good to the mortar colour
- Certified bonded bead system
- Regulations route and guarantee named on the quote
- Binder applied at the nozzle
Guide prices for Caernarfon
| Bonded polystyrene bead 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 Caernarfon property:
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.