Cavity wall insulation for Streatham properties
Our Greater London coverage takes in Streatham (SW16) and nearby Mitcham, Brixton and Wimbledon. It is about 6 miles south of London.
Most Streatham houses built from the 1920s onwards have cavity walls, but the survey still checks each one: cavity width, debris, the condition of the brickwork and how exposed each wall is. If a wall in Streatham 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.
Local weather affects which walls can be filled. 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.
On compliance, in Streatham 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 Streatham
- Certified mineral wool or bonded bead system
- Guarantee and installer named on your quote
- Suitability survey with photos and a written result
- Borescope check where the cavity is in doubt
Guide prices for Streatham
| Cavity wall insulation guide prices | Guide 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.
From enquiry to finish in Streatham:
Tell us about the property
Postcode, property type and what you need.
Free survey
Walls, cavity, condition and exposure checked and photographed.
Written result and price
Suitable, suitable after repairs, or not suitable, with a fixed price.
Work and paperwork
Installation, making good, and the regulations and guarantee paperwork.