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Gwynedd · Wales

Cavity wall suitability survey in Gwynedd

A cavity wall survey checks whether your walls can safely be filled and with what. Our Gwynedd coverage includes Bangor, Caernarfon, Holyhead and the towns around them.

Surveyor measuring the wall thickness at a window reveal of a brick house

Book a survey in Gwynedd

Free with an install quote; standalone reports are priced before you book.

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Cavity wall suitability survey across Gwynedd

We cover 4 towns in Gwynedd: Bangor, Caernarfon, Holyhead and Porthmadog.

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.

Buyers and sellers in Gwynedd often book this check when a survey report or EPC raises questions about the walls. Where a Gwynedd wall shows cold patches or damp, the survey targets those areas first rather than sampling at random.

Building Regulations in Wales

In Wales, filling an existing cavity is also notifiable building work under the Building Regulations as they apply in Wales. A registered installer normally self-certifies it through a competent person scheme; otherwise a building notice goes to your council's building control before work starts. Welsh rules can differ from England's, so the notification route is confirmed in writing on your quote.

Sources: Welsh Government: building work competent person schemes; CIGA: CWISC competent person scheme; Welsh Government: issues arising from cavity wall insulation installations.

What you get

A clear result: suitable, suitable after repairs, or not suitable. Where repairs are needed first, they are listed and priced separately so you can choose who does them. The survey is free when you are getting an install quote.

What is included

  • Photo-backed written result
  • Cavity width and debris check
  • Exposure assessment by elevation
  • Repairs list where needed
  • Fixed install price where suitable

Cavity wall suitability survey prices in Gwynedd

Cavity wall suitability survey guide prices
Cavity wall suitability survey guide pricesGuide price
Suitability survey with an install quoteFree
Standalone survey report (no install quote)£145–£245

The survey is free with an install quote. A standalone report is not insulation, so it is normally standard-rated for VAT; guide prices include VAT. 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 Gwynedd property:

  1. Tell us about the property

    Postcode, property type and why you need the survey.

  2. Survey visit

    Walls, cavity, condition and exposure checked and photographed.

  3. Written result

    Suitable, suitable after repairs, or not suitable.

  4. Fixed price if you want work

    The survey is free when it is for an install quote.

Last reviewed 19 October 2026.

Cavity wall suitability survey in Gwynedd: questions

Do you cover all of Gwynedd?

Yes. We cover 4 towns across Gwynedd, including Bangor, Caernarfon, Holyhead and Porthmadog, and the villages around them. Island and remote addresses are surveyed by arrangement.

Is there VAT on a cavity wall survey in Gwynedd?

The survey is free when it is for an install quote. A standalone survey report is not insulation, so it is normally standard-rated for VAT, and the price you are quoted includes it.

Is my Gwynedd home too exposed for cavity insulation?

Parts of Gwynedd get some of the heaviest wind-driven rain in the UK, so the survey is stricter and some walls are better left unfilled. The survey records the exposure of each wall before recommending a material, or recommending against filling.

Is the survey free in Gwynedd?

Yes when it is for an install quote. Standalone reports for Gwynedd buyers, sellers or landlords who do not need an install quote are priced before you book.

Cavity wall suitability survey in nearby areas

Book a survey in Gwynedd

Free with an install quote. Written result for every wall.