Floor Insulation — Stop Heat Escaping Beneath Your Feet
Cold floors and draughts between floorboards are a sign that heat is escaping downwards. Insulating the ground floor tackles both.
Lofts and walls usually come first, but a ground floor with no insulation still lets heat escape — especially suspended timber floors, where cold air can move under the boards. Floor insulation saves less than loft or wall insulation, so it is often best done when floors are already being lifted, or as part of a wider plan.
- Typical yearly saving
- £40–£100
- Suspended timber floor, typical cost
- £1,400–£2,500
- On installed insulation until 31 March 2027
- 0% VAT
What Is Floor?
For suspended timber floors, insulation such as mineral wool or rigid boards is fitted between the joists — from a cellar or crawl space if there is one, or by lifting the floorboards. Solid concrete floors can be insulated by laying rigid boards on top and a new floor surface, which raises the floor level and costs considerably more.
How It Works
Floor Check
The installer identifies the floor type and checks the joists for damp or rot, the ventilation under the floor, and access.
Preparation
Floorboards are lifted if there is no access from below. Any damp or timber problems are fixed first.
Installation
Insulation is fitted snugly between the joists without gaps, keeping air bricks and under-floor ventilation clear.
Finishing
Floorboards are relaid and gaps at the skirting sealed, or a new floor surface is laid over a solid floor.
Is It Right for My Home?
Most ground floors can be insulated. Suspended timber floors are the easiest, particularly with access from a cellar or crawl space. Only insulate if the joists are in good condition, and make sure under-floor ventilation is kept. Upstairs flats and floors above heated rooms usually do not need it.
Key Benefits
Warmer Floors
Ground-floor rooms feel more comfortable underfoot.
Fewer Draughts
Insulating and sealing a suspended floor cuts draughts coming up between the boards.
Lower Energy Bills
Around £55 a year for an average house and up to £100 for a detached bungalow (Energy Saving Trust).
Works With Other Measures
Best combined with loft and wall insulation for a warmer home overall.
Good Time: Floor Already Up
If you are replacing floors or doing other work, adding insulation at the same time keeps the extra cost down.
Lower Carbon Emissions
Less heat loss means less heating and lower emissions.
Ask for a Free Floor Quote
Typical Costs and Savings
Typical figures to help you compare, not a quote for your home. Your costs and savings depend on the property, how you heat it and how you use energy.
| Example | Typical Cost | Typical Saving a Year |
|---|---|---|
| Detached house | £1,400–£2,500 | £85 |
| Semi-detached house | £1,400–£2,500 | £55 |
| Mid-terrace house | £1,400–£2,500 | £40 |
| Detached bungalow | £1,400–£2,500 | £100 |
Energy Saving Trust estimates for insulating under the floorboards of a gas-heated home, based on fuel prices as of July 2026. The cost range is the Energy Saving Trust's typical price for a suspended floor depending on house type; solid floors cost considerably more. Source: Energy Saving Trust — floor insulation. Last reviewed September 2026.
Help With the Cost
Funding depends on where you live, your income and your home, and schemes change. We are not a government body — check the official scheme before relying on it.
Warm Homes: Local Grant (England)
Council-run funding that can include underfloor insulation for lower-income households living in homes rated EPC D–G.
Read more on our grants guide →0% VAT until 31 March 2027
Professionally installed insulation in a home is zero-rated for VAT until 31 March 2027.
Read more on our grants guide →Frequently Asked Questions
Your next step
Thinking about Floor Insulation?
It is free to ask and there is no obligation.