Loft insulation is one of the most cost-effective ways to improve energy efficiency for both homes and businesses across the UK. However, the cost of loft insulation can vary significantly depending on the size of the property, the type of insulation material used, and whether professional installation is required.
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This guide covers all the main costs to insulate a loft, including material prices, labour charges, additional services, grants, and VAT considerations for domestic and commercial properties.
Average loft insulation costs in the UK (2025 update)
| Type of cost | Typical range (domestic) | Typical range (commercial) |
|---|---|---|
| Material only (per m²) | £5 – £15 | £7 – £20 |
| Full installation (labour + materials, detached house) | £400 – £700 | £600 – £1,200 |
| Full installation (labour + materials, semi-detached) | £300 – £600 | £500 – £1,000 |
| Full installation (labour + materials, terraced) | £250 – £500 | £400 – £900 |
| Loft boarding (optional, per m²) | £25 – £50 | £30 – £60 |
| Loft hatch upgrade (optional) | £100 – £250 | £150 – £350 |
| Insulation removal (if needed) | £300 – £600 | £500 – £1,000 |
| Energy performance certificate (EPC, optional) | £60 – £120 | £80 – £180 |
Note: All prices include VAT where applicable, based on a 5% rate for energy-saving materials in homes and standard 20% VAT in commercial cases (unless exemptions apply).
Key factors affecting loft insulation costs
Property size and access
Larger loft spaces cost more due to increased material and labour requirements. Difficult-to-access lofts (e.g., small hatches, steep angles) may add £100–£300 to the final price due to additional work.
Type of insulation material
- Mineral wool (glass or rock wool): £5–£10 per m². Cheapest and most common.
- Sheep’s wool insulation: £12–£20 per m². Natural and breathable but pricier.
- Spray foam insulation: £30–£50 per m². Best for hard-to-reach spaces, but expensive and less environmentally friendly.
- Multifoil insulation: £10–£20 per m². Thin, space-saving option.
- Rigid board insulation (PIR boards like Celotex): £15–£30 per m². High thermal performance, often used in business settings.
Labour costs
Professional installation typically costs £150–£300 per day per worker. Most domestic lofts take 1–2 days. Larger or more complex commercial projects may require longer, especially if special equipment like scaffolding or fall protection is needed.
Additional work
- Old insulation removal: If existing insulation is damp, mouldy, or damaged, it must be removed, adding £300–£600.
- Loft cleaning and pest control: Around £100–£400 depending on condition.
- Loft boarding: Many businesses board the loft to store documents and equipment, adding to costs.
- Upgraded loft hatch and ladder: A secure access solution for regular use, priced at £100–£350 depending on specification.
Typical total project examples
- Small terraced house (domestic, new insulation): £300 – £500
- Detached 4-bedroom house (domestic, removal + install): £700 – £1,000
- Small business premises (office loft, rigid board insulation + boarding): £1,500 – £2,500
- Large commercial warehouse (spray foam insulation): £8,000 – £15,000+
Government grants and schemes to help with the cost of loft insulation
For domestic homes, the UK Government offers several incentives:
- ECO4 scheme: Covers all or part of the cost for low-income households.
- Local authority grants: Some councils offer specific insulation funding.
- VAT reduction: Energy-saving measures in homes attract a reduced 5% VAT rate.
Businesses, however, typically do not qualify for domestic insulation grants, although enhanced capital allowances (ECAs) or green funding schemes may be available for energy improvements.
Hidden or overlooked costs to be aware of
- Damp or condensation treatment: Installing insulation without addressing damp issues can worsen problems. Treatment may cost £500 – £2,000.
- Upgrading ventilation: Prevents moisture build-up post-insulation. Adding roof vents costs £100–£300.
- Thermal bridging solutions: May be necessary for older commercial buildings at an extra £500–£1,500.
Conclusion – How much should you budget for the cost to insulate a loft?
- Domestic homes: £300–£800 for standard mineral wool insulation; more for upgrades or removal.
- Small businesses: £1,000–£3,000 depending on size and material choice.
- Large commercial properties: £5,000–£20,000+, particularly for spray foam or specialist work.
Professional advice is recommended to assess your property and ensure you meet building regulations, particularly for businesses that may need to comply with more stringent energy performance standards.