Cavity insulation for new builds and extensions for Windsor properties
Our Berkshire coverage takes in Windsor (SL4) and nearby Slough, Maidenhead and Bracknell. It is roughly 16 miles east of Reading.
If a wall in Windsor 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 Windsor property has an extension or a conservatory, we check how the old and new walls meet, because that junction is often missed.
Local weather affects which walls can be filled. Much of Berkshire 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.
On the rules side, in Windsor 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 Windsor
- Trays, closers and stop ends as drawn
- Batts or boards to the specified U-value
- Clean-cavity working
- Photo record for building control
Guide prices for Windsor
| Cavity insulation for new builds and extensions guide prices | Guide 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.
The steps for cavity insulation for new builds and extensions in Windsor:
Get in touch
Online, by phone or WhatsApp, whichever suits you.
Survey visit
The surveyor checks each wall and looks into the cavity where needed.
Your result in writing
What we found, what it means, and a fixed price if work is needed.
Booked work
Carried out by the installer named on your quote, with their scheme registrations.