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Superfoil Insulation
Superfoil Insulation
Thin, multi-layer foil insulation for roof slopes, loft conversions and other spaces where thickness matters. Understand how it works before you choose it.
Understand your options
What is superfoil insulation?
Superfoil is a brand of multifoil insulation: thin layers of reflective foil separated by wadding or foam. Part of its performance comes from reflecting heat across air gaps on either side, so those gaps, the overlaps and the taped joints all have to be installed as the manufacturer specifies.
It is often chosen where space is tight, such as roof slopes in loft conversions, and is frequently combined with other insulation to reach the level of insulation a project needs.
What to check
How well multifoil performs varies between products and depends on how it is installed. Ask for the product's third-party certificate, such as a British Board of Agrément (BBA) certificate, and for a U-value calculation for your roof or wall. Loft conversions and many renovation projects need building regulations approval, so check with your building control body that the proposed build-up will be accepted before work starts.
Last reviewed September 2026.
Tell us about your project and we will pass it to Better Home Hub, which looks for a specialist who covers your area. The specialist assesses the space and provides the quote.
From enquiry to installation
Your next steps, made clear.
Arrange an assessment
A specialist looks at the space, existing insulation, ventilation and any damp, and proposes a build-up.
Check the specification
Ask for the product certificate and a U-value calculation, and confirm with building control where approval is needed.
Installation
Battens create the air gaps, the multifoil is fixed with the specified overlaps and all joints are taped before finishing.
How does multifoil insulation work?
It combines reflective foil layers, which reflect radiant heat across the air gaps next to them, with wadding or foam layers that slow heat moving through. Without the air gaps it loses much of its benefit.
Is multifoil as good as thicker insulation?
It depends on the product and the installation. In many roofs, multifoil alone will not reach the level required, so it is combined with other insulation. Ask for a U-value calculation for your specific build-up.
Where can I use Superfoil insulation?
It is most often used on roof slopes and in loft conversions, and sometimes in walls, floors and outbuildings. Check the product certificate covers the use you have in mind.
Does it need an air gap?
Yes. Reflective insulation relies on air gaps next to the foil, usually created with battens. The size and position of the gaps should follow the manufacturer's instructions.
Will it meet building regulations?
It can, when the product is certified for the use and the build-up is correctly specified and installed. Building control decides whether a project complies, so check with them before work starts.
Does multifoil act as a vapour barrier?
Some products are designed to act as a vapour control layer and others are breathable. Ask which type is proposed and why, as the wrong choice can cause condensation.
Your next step
A warmer home.
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