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Newtown · Powys

Cavity insulation for new builds and extensions in Newtown

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 Newtown and the wider SY16 postcode district, with the survey, result and fixed price all in writing.

Free survey in Newtown

Covering Newtown and the SY16 district. Tell us about the property and we will arrange a free survey and a fixed price.

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Cavity insulation for new builds and extensions for Newtown properties

Newtown is among the towns we cover in Powys, alongside Welshpool and Llandrindod Wells. Newtown is one of the main towns we cover in Powys.

Newtown properties with rendered or painted walls get a closer look at the outer finish, because cracked render can let rain behind it. Where a Newtown property has an extension or a conservatory, we check how the old and new walls meet, because that junction is often missed.

Wind-driven rain is the first thing the surveyor weighs up. Parts of Powys 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 the rules side, in Newtown 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 Newtown

  • Trays, closers and stop ends as drawn
  • Coordination with your bricklayers
  • Batts or boards to the specified U-value
  • Clean-cavity working

Guide prices for Newtown

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 Newtown:

  1. Tell us about the property

    Postcode, property type and what you need.

  2. Free survey

    Walls, cavity, condition and exposure checked and photographed.

  3. Written result and price

    Suitable, suitable after repairs, or not suitable, with a fixed price.

  4. Work and paperwork

    Installation, making good, and the regulations and guarantee paperwork.

Last reviewed 19 October 2026.

Cavity insulation for new builds and extensions in Newtown: questions

Do you cover Newtown?

Yes. Newtown and the SY16 postcode district are within our Powys coverage, along with nearby Welshpool and Llandrindod Wells.

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

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

Is my Newtown home too exposed for cavity insulation?

Parts of Powys 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.

How soon can you visit in Newtown?

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 Newtown

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