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Coulsdon · Greater London

Cavity wall insulation in Coulsdon

Cavity wall insulation fills the gap between the two leaves of a brick or block wall with a certified insulating material, blown in through small holes drilled from outside. We cover Coulsdon and the wider CR5 postcode district, with the survey, result and fixed price all in writing.

Free survey in Coulsdon

Covering Coulsdon and the CR5 district. Tell us about the property and we will arrange a free survey and a fixed price.

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Cavity wall insulation for Coulsdon properties

Coulsdon sits in Greater London, roughly 13 miles south of London. We work across the CR5 district, including nearby Purley, Wallington and Sutton.

Coulsdon properties with rendered or painted walls get a closer look at the outer finish, because cracked render can let rain behind it. A suitable wall in Coulsdon is usually filled in a single day from outside, with drill holes made good to match the pointing.

Every elevation is judged on its own exposure. Much of Greater London 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.

In terms of approvals, in Coulsdon 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 happens on the day?

Holes of around 22mm are drilled in the mortar joints in a set pattern, roughly a metre apart. The insulation is blown in from the bottom up until each section is full, then every hole is filled with colour-matched mortar. Air bricks and flues are protected, and a cavity barrier is fitted where your wall joins a neighbour's.

What is included in Coulsdon

  • Building regulations route for your nation, confirmed in writing
  • Guarantee and installer named on your quote
  • Cavity barriers at party walls
  • Suitability survey with photos and a written result

Guide prices for Coulsdon

Cavity wall insulation guide prices
Cavity wall insulation guide pricesGuide price
Detached house£2,295–£3,795
Semi-detached house£1,495–£2,495
End-terrace house£1,295–£2,195
Detached bungalow£1,295–£2,195
Semi-detached bungalow£895–£1,595
Mid-terrace house£795–£1,395

No VAT is charged on installing insulation in homes until 31 March 2027 (then 5%). 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.

The steps for cavity wall insulation in Coulsdon:

  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 wall insulation in Coulsdon: questions

Is there VAT on cavity wall insulation in Coulsdon?

Installing insulation in a home is currently zero-rated for VAT until 31 March 2027, then 5%. Commercial buildings are standard-rated.

Is the survey free in Coulsdon?

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

Do you cover Coulsdon?

Yes. Coulsdon and the CR5 postcode district are within our Greater London coverage, along with nearby Purley and Wallington.

How much does cavity wall insulation cost in Coulsdon?

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

Nearby towns

Book a free survey in Coulsdon

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