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Farnham · Surrey

Cavity insulation for new builds and extensions in Farnham

Looking for cavity insulation for new builds and extensions in Farnham? 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 Farnham

Covering Farnham and the GU9 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 Farnham properties

Farnham sits in Surrey, roughly 10 miles west of Guildford. We work across the GU9 district, including nearby Godalming, Camberley and Guildford.

A suitable wall in Farnham is usually filled in a single day from outside, with drill holes made good to match the pointing. If a wall in Farnham 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.

Every elevation is judged on its own exposure. Much of Surrey sits in the more sheltered driving-rain zones of the UK, which widens the choice of fill. Exposed elevations, coastal sites and high ground still get checked wall by wall.

For regulations, in Farnham 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.

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 Farnham

  • Coordination with your bricklayers
  • Clean-cavity working
  • Photo record for building control
  • Batts or boards to the specified U-value

Guide prices for Farnham

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 Farnham:

  1. Send your details

    A minute online, or call the free number.

  2. We check the walls

    Construction, cavity width, debris, damp and wind-driven rain exposure.

  3. You decide

    Plain-English result and a fixed price, with no pressure to book.

  4. Job done properly

    Holes made good, paperwork handed over, guarantee details confirmed.

Last reviewed 19 October 2026.

Cavity insulation for new builds and extensions in Farnham: questions

Do you cold-call in Farnham?

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

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

How soon can you visit in Farnham?

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.

Do you work on rented homes in Farnham?

Yes. Landlords and agents in Farnham can book batch visits, and work is arranged around tenants.

Nearby towns

Book a free survey in Farnham

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