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Seaford · East Sussex

Cavity insulation for new builds and extensions in Seaford

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 Seaford and the wider BN25 postcode district, with the survey, result and fixed price all in writing.

Free survey in Seaford

Covering Seaford and the BN25 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 Seaford properties

If your property is in Seaford or the BN25 district or nearby Rottingdean, Eastbourne and Hailsham, it is within our East Sussex coverage. It is about 11 miles east of Brighton.

If a wall in Seaford 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. Where a Seaford 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. East Sussex 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.

For regulations, in Seaford 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 Seaford

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

Guide prices for Seaford

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.

How it works in Seaford:

  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 Seaford: questions

Which building regulations route applies in Seaford?

Seaford is in England, so filling a cavity is notifiable building work and needs a building notice or competent-person self-certification. We confirm the route in writing on your quote.

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

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.

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

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

Is my Seaford home too exposed for cavity insulation?

East Sussex has a mix of moderate and more exposed sites, so each wall is judged on its own. The survey records the exposure of each wall before recommending a material, or recommending against filling.

Nearby towns

Book a free survey in Seaford

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