The numbers
| Item | Indicative cost | Notes |
|---|---|---|
| Single-layer reflective foil, material | £8 – £15 per m² | Bubble or foam core; DIY outbuildings |
| Certified multifoil, material | £15 – £30 per m² | SuperFOIL, SuperQuilt and equivalents; add tape |
| Multifoil to rafters, installed | £45 – £80 per m² | Battens, tape, labour; exposed finish |
| Multifoil + PIR to rafters, installed | £65 – £110 per m² | Where the certificate requires PIR to meet 0.18 |
| Plasterboard and skim over | £25 – £45 per m² | Loft room finish |
| Typical semi-detached roof, installed | £2,000 – £6,500 | 50–80 m² of slope, exposed finish |
How we estimate these costs
Every figure on this page is an estimate built from four sources, in this order of weight: (1) published retail prices for named products at national merchants and specialist multifoil stockists, checked on 3 September 2026; (2) installer quotations and rate cards shared with InsulationMatch for typical rafter, room-in-roof and floor jobs; (3) published UK trade cost guides and third-party pricing surveys, used only to sanity-check the range; (4) labour assumptions of one to three days for a typical semi-detached roof slope pair at regional trade day rates. Figures are shown as ranges because access, roof geometry, existing insulation and finish move real prices by more than any single point estimate. We do not yet hold enough InsulationMatch project pricing to publish first-party data; as anonymised quotations and completed-project prices accumulate, this page will show InsulationMatch project pricing data by region, property type and system, dated, and the estimates will be retired. We do not use the word “verified” for these figures because we cannot independently verify every quote they draw on; they are compiled and reviewed.
Same roof, three materials
For a 60 m² roof slope brought to 0.18 W/m²K: multifoil with 50mm PIR, roughly £4,000–£6,500 installed at 75mm below the rafters; PIR between and under rafters, roughly £3,500–£6,000 at 100mm+ below; mineral wool between rafters with PIR under, roughly £3,000–£5,000 at 100mm+ below. The premium for multifoil is the headroom. In an open loft that premium is hard to justify; in a loft room it is often the cheapest way to keep the ceiling height.
Up to two vetted installers, each required to show the build-up and ventilation path in writing.
What moves the price
- Access. An open loft is easy. A finished loft room means stripping plasterboard first.
- Roof shape. Dormers, valleys and hips add cutting and taping time.
- Ventilation work. Adding eaves vents or a ridge vent where none exist.
- Existing material. Old insulation or spray foam removed first. Spray foam removal cost.
- Finish. Exposed foil in a storage loft versus plastered and decorated in a bedroom.
Is there funding?
Not for foil as a product. Room-in-roof insulation can be a funded measure for eligible households; the installer chooses the material. Current routes.
Questions homeowners ask
Is multifoil cheaper than PIR?
How much does SuperFOIL installation cost?
Is foil insulation VAT-free?
- Checkatrade — Loft insulation cost guide — checked 2 September 2026
- MyBuilder — Loft insulation cost guide — checked 2 September 2026
- SuperFOIL — product range — checked 2 September 2026