Heating · Updated 2026
Loft insulation cost
Typical range£150–£6,000· Average loft insulation cost (3 bed, top-up to 270mm)
Loft insulation prices for 2025 — topping up and first-time installation. In the UK, expect to pay between £150 and £6,000, with the typical project around £400 (average loft insulation cost (3 bed, top-up to 270mm)). Regional variation, specification tier and site access conditions all shift the final quote.
Quick answer: Loft insulation cost in the UK typically costs between £150 and £6,000 (Average loft insulation cost (3 bed, top-up to 270mm)). London and the South East run 20–35% above this range; the North, Wales and most of Scotland sit 5–15% below.
Homeowners researching this typically also price up cavity wall insulation cost and solid wall insulation cost. For wider context, browse our bathroom pricing, kitchen pricing and trades day rates.
Cost table
Indicative price ranges (UK, GBP)
| Item | Typical range (GBP) |
|---|---|
Mineral wool top-up (3 bed) — Topping up existing insulation to 270mm | £150–£600 |
First-time loft insulation (3 bed) — Between and over joists, 270mm total | £400–£1,000 |
Loft insulation + hatch upgrade — Insulated hatch door included | £500–£1,200 |
Spray foam loft insulation — Closed-cell, good for hard-to-access lofts | £800–£3,000 |
Rigid board (warm roof conversion) — For converting loft to habitable space | £1,500–£6,000 |
Labour costs
Labour typically accounts for 50% of the total project cost in the UK.
Labour line items
| Item | Typical range (GBP) |
|---|---|
Insulation installer (per day) | £150–£280/day |
Clearance / boarding removal | £100–£300 |
Materials costs
Materials and fittings make up the remainder of the budget, with specification tier driving most of the variation.
Materials & fittings
| Item | Typical range (GBP) |
|---|---|
Mineral wool roll (100mm, per m²) | £3–£6/m² |
Mineral wool roll (170mm, per m²) | £5–£9/m² |
Blown fibre (loose fill, per m²) | £6–£12/m² |
Rigid PIR board (per m²) | £15–£35/m² |
Insulated loft hatch | £80–£250 |
Factors affecting cost in the UK
- ·Region — London and the South East run 15–30% above national averages.
- ·Specification tier — premium materials and finishes can double the base cost.
- ·Access and site conditions — flats, restricted parking and listed buildings add time.
- ·Scope changes mid-project — late design decisions are the biggest cost overrun driver.
- ·Trade availability — quotes rise 10–20% in peak spring and summer months.
Ways to reduce cost
- ·Check ECO4 or Great British Insulation Scheme grant eligibility before paying.
- ·Use mineral wool batts laid DIY — material cost is £4–£8/m², zero labour.
- ·Top up existing 100 mm to 270 mm rather than stripping and starting over.
- ·Insulate the loft hatch and pipework at the same time for marginal extra cost.
- ·Combine with cavity wall insulation through a single ECO-registered installer.
Frequently asked questions
- How much does loft insulation save per year?
- The Energy Saving Trust estimates that insulating an uninsulated loft saves around £150–£200 per year on heating bills in a typical semi-detached home. Topping up existing thin insulation saves £50–£100/year.
- Is spray foam insulation bad for mortgages?
- Yes — spray foam insulation in the roof space has caused significant problems for mortgage lenders and surveyors. Many lenders refuse to lend on properties with spray foam. The foam is difficult to remove and can mask roof defects. It should be approached with great caution.
- Can I insulate my loft myself?
- Yes — fitting mineral wool loft insulation is one of the most accessible DIY energy upgrades. Wear a dust mask and gloves, and ensure you insulate the hatch too. Blown fibre requires specialist equipment.
- What is the recommended depth of loft insulation?
- The UK government recommends 270mm total depth (two layers — 100mm between joists, 170mm across the joists). Many older homes have only 100mm or less.