Underfloor insulation for Portsmouth properties
Our Hampshire coverage takes in Portsmouth (PO1) and nearby Gosport, Fareham and Havant. It is around 16 miles south-east of Southampton.
In Portsmouth homes this is often done on the same visit as a cavity fill, which saves a second trip. Small measures like this are often among the cheapest per pound saved, and they suit Portsmouth homes of every age.
For regulations, if cavity wall insulation follows in Portsmouth, 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.
Keeping the void ventilated
Air bricks under a suspended floor must stay clear so the timbers stay dry. Insulation goes between the joists, not across the void, and gaps at skirtings are sealed to stop draughts.
What is included in Portsmouth
- Boards relaid
- Floor void inspection
- Draught sealing at skirtings
- Insulation between joists
Guide prices for Portsmouth
| Underfloor insulation guide prices | Guide price |
|---|---|
| Suspended timber floor, typical room | £795–£1,495 |
| Whole ground floor | £1,995–£3,995 |
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.
How it works in Portsmouth:
Get in touch
Online, by phone or WhatsApp.
Survey visit
We check the space, what is there now and how it is ventilated.
Your quote in writing
A fixed price, with any extras listed separately.
Booked work
Carried out by the installer named on your quote.