Underfloor insulation cost: 2026 UK breakdown by floor type

Suspended timber floor (from below)

Cost: £700 to £1,500 per room (20m² living room).

What it includes:

• 100mm PIR boards or 150mm mineral wool batts between joists.
• Netting or timber battens to support the insulation.
• Labor (working from cellar or crawl space).

Whole ground floor: £1,800 to £3,500 (3-bed semi).

DIY cost: £300 to £600 per room (materials only).

Suspended timber floor (from above)

Cost: £1,200 to £2,500 per room.

What it includes:

• Lifting floorboards.
• Fitting insulation between joists (with netting underneath).
• Re-laying floorboards or replacing with chipboard.
• Re-decoration.

More expensive because you have to lift and re-lay the floor. Only worth it if you're already lifting the floor for another reason (rewiring, replumbing).

Solid concrete floor

Cost: £2,500 to £6,000 for a whole ground floor.

What it includes:

• Lifting existing floor (screed, tiles, or boards).
• Laying 100mm to 150mm insulation boards (EPS or PIR).
• Pouring new screed (75mm to 100mm).
• Re-laying flooring (tiles, vinyl, or laminate).
• Re-fitting skirting.

Very disruptive. Only worth it during major renovation. Payback is 25 to 40 years.¹

What affects the price?

• Access: From below is cheaper than from above.
• Floor area: Larger rooms cost more (but cost per m² drops).
• Floor type: Suspended is cheaper than solid.
• Existing floor condition: If your floor is damp or the joists are rotten, you need repairs first (adds £500 to £2,000).
• Material choice: PIR is more expensive than mineral wool or EPS, but thinner.

Grants and savings

Floor insulation is not usually covered by ECO4. You may qualify for the Home Upgrade Grant if you have off-gas heating and low income.²

Savings: £40 to £100 per year depending on floor type. Payback: 12 to 40 years.

Related reading

• Is floor insulation worth it?
• Suspended floor insulation guide
• Concrete floor insulation guide