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Barry · South Glamorgan

Cavity insulation for new builds and extensions in Barry

For new walls the cavity is insulated as it is built, using full-fill mineral wool batts or partial-fill boards fixed to the inner leaf. We cover Barry and the wider CF62 postcode district, with the survey, result and fixed price all in writing.

Free survey in Barry

Covering Barry and the CF62 district. Tell us about the property and we will arrange a free survey and a fixed price.

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We use your details only to answer this enquiry and arrange your visit, sharing them only with the registered installer we appoint for your job and the providers named in our privacy notice. No marketing lists, no cold calls.

Cavity insulation for new builds and extensions for Barry properties

We cover Barry and the CF62 postcode district, including nearby Penarth and Cardiff. It is about 7 miles south-west of Cardiff.

For semi-detached and terraced homes in Barry, cavity barriers are fitted where your wall meets your neighbour's so the fill stays on your side. Barry properties with rendered or painted walls get a closer look at the outer finish, because cracked render can let rain behind it.

Every elevation is judged on its own exposure. Parts of South Glamorgan 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 Barry 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 Barry

  • Photo record for building control
  • Clean-cavity working
  • Trays, closers and stop ends as drawn
  • Batts or boards to the specified U-value

Guide prices for Barry

Cavity insulation for new builds and extensions guide prices
Cavity insulation for new builds and extensions guide pricesGuide 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.

From enquiry to finish in Barry:

  1. Get in touch

    Online, by phone or WhatsApp, whichever suits you.

  2. Survey visit

    The surveyor checks each wall and looks into the cavity where needed.

  3. Your result in writing

    What we found, what it means, and a fixed price if work is needed.

  4. Booked work

    Carried out by the installer named on your quote, with their scheme registrations.

Last reviewed 19 October 2026.

Cavity insulation for new builds and extensions in Barry: questions

How much does cavity insulation for new builds and extensions cost in Barry?

Our guide ranges for cavity insulation for new builds and extensions are shown on this page. The fixed price for your Barry property is confirmed in writing after the survey, before any work starts.

Is there VAT on cavity insulation for new builds and extensions in Barry?

Building a new home is usually zero-rated when supplied by the builder; supply-only materials are standard-rated. The VAT treatment is confirmed on your quote.

Do you cold-call in Barry?

No. We only come out when you have asked us to. If someone cold-calls offering free insulation, check before you agree to anything.

How soon can you visit in Barry?

We arrange dates when you get in touch. Availability varies through the year, so we give you real dates rather than a promise on the website.

Nearby towns

Book a free survey in Barry

Free survey with an install quote. Written result. Fixed price before any work.