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Falmouth · Cornwall

Cavity insulation for new builds and extensions in Falmouth

Falmouth homeowners, landlords and managing agents can book cavity insulation for new builds and extensions with a free survey first. 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 Falmouth

Covering Falmouth and the TR11 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 Falmouth properties

If your property is in Falmouth or the TR11 district or nearby Truro, Redruth and Camborne, it is within our Cornwall coverage. It is roughly 7 miles south of Truro.

Falmouth properties with rendered or painted walls get a closer look at the outer finish, because cracked render can let rain behind it. If a wall in Falmouth is not suitable, for example because of an undiagnosed damp patch or a very exposed gable, you are told so in writing with the reason.

Exposure matters for every cavity wall. Parts of Cornwall 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 Falmouth 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 Falmouth

  • Clean-cavity working
  • Coordination with your bricklayers
  • Trays, closers and stop ends as drawn
  • Photo record for building control

Guide prices for Falmouth

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 Falmouth:

  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 Falmouth: questions

Is my Falmouth home too exposed for cavity insulation?

Parts of Cornwall 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 Falmouth?

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.

Is the survey free in Falmouth?

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

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

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.

Nearby towns

Book a free survey in Falmouth

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