SuperFoil Multifoil
Multifoil insulation, such as SuperFOIL, is made of thin layers of reflective foil and wadding. It is much thinner than mineral wool or rigid board, which is why it is sometimes used in loft conversions where headroom is tight. On its own its thermal resistance is modest, so it is usually combined with other insulation to meet building regulations. How well it performs depends on the product and on correct installation, including air gaps.
What to Know About SuperFoil Multifoil
- Thin and flexible, so it takes up little headroom
- Often used alongside other insulation in a converted loft
- The manufacturer quotes a tested R-value of 2.49 m²K/W for SuperFOIL SF19+ in roofs
- Can form part of the vapour control layer when joints are taped as the manufacturer specifies
- Performance depends on correct air gaps and installation — ask for the build-up to be checked
Price Guide
From about £14/m² (materials only)
Typical UK price guide, last reviewed September 2026. A guide, not a quote.
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Frequently Asked Questions
Is SuperFoil as good as traditional insulation?
Not like for like. The manufacturer quotes a tested R-value of 2.49 m²K/W for SuperFOIL SF19+ in a roof, which is far less than a full 270mm layer of mineral wool, so multifoil is usually combined with other insulation to reach building regulations standards in a loft conversion. Its advantage is thinness. Ask your designer or building control to confirm the full build-up meets the required U-value.
Can SuperFoil be used in a loft conversion?
It can form part of the insulation in a loft conversion, usually combined with other insulation. The manufacturer says its products hold BBA approval and LABC registration; ask your designer or building control body to confirm that the product and installation method are accepted for your roof before work starts.
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