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Weymouth · Dorset

Cavity insulation for new builds and extensions in Weymouth

Looking for cavity insulation for new builds and extensions in Weymouth? We survey first, name the installer, their scheme registrations and the guarantee on the quote, and only then book the work. 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.

Free survey in Weymouth

Covering Weymouth and the DT4 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 Weymouth properties

Weymouth is among the towns we cover in Dorset, alongside Poole, Bournemouth and Christchurch. It is around 27 miles west of Bournemouth.

A suitable wall in Weymouth is usually filled in a single day from outside, with drill holes made good to match the pointing. For semi-detached and terraced homes in Weymouth, cavity barriers are fitted where your wall meets your neighbour's so the fill stays on your side.

Local weather affects which walls can be filled. Dorset has a mix of moderate and more exposed sites. Hilltop, coastal and west-facing walls take the brunt of wind-driven rain, so the survey records exposure for each elevation before a material is chosen.

On the rules side, in Weymouth filling a cavity is notifiable building work and needs a building notice or competent-person self-certification.

Funding in England

In England, ECO4 runs to 31 December 2026 and Warm Homes: Local Grant supports low-income households through councils.

Sources: GOV.UK: extending the ECO4 end date, government response; GOV.UK: Warm Homes Plan.

Extensions that join an older house

Where an extension meets an existing cavity wall, the junction is a weak point. We can borescope and fill the existing wall at the same time so the old and new walls perform together.

What is included in Weymouth

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

Guide prices for Weymouth

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.

What happens next for a Weymouth property:

  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 Weymouth: questions

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

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.

Is the survey free in Weymouth?

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

Do you cold-call in Weymouth?

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

Are there grants for insulation in Weymouth?

In England, ECO4 runs to 31 December 2026 and Warm Homes: Local Grant supports low-income households through councils. We cannot promise funding, but we will point you to the right official route.

Nearby towns

Book a free survey in Weymouth

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