Buying guide
About SuperFOIL Insulation
SuperFOIL insulation offers a range of lightweight, reflective multifoil and underfloor insulation products designed to improve thermal efficiency without taking up as much space as some traditional insulation systems. However, choosing the right product depends on your building, available installation depth, moisture requirements and target thermal performance.
This guide compares five popular options: SFUF, SF6, SF19BB, SF19+ and SF40, explaining where each is best suited.
SuperFOIL SFUF: Best for Suspended Timber Floors
SFUF is a specialist underfloor insulation product designed for suspended timber floors. At approximately 6mm thick, it is particularly useful where there is limited clearance beneath floorboards or where raising the finished floor level is undesirable.
It can help reduce draughts, cold spots and heat loss through timber floors, making it worth considering during renovations and home improvement projects.
Choose SFUF when: you want a dedicated, thin insulation solution for an existing suspended floor. For projects requiring substantial thermal improvements, assess whether additional insulation is needed to meet your target U-value.
SuperFOIL SF6: Best for Basic Insulation Projects
SF6 is a 30mm-thick multifoil insulation product suitable for roofs, walls and floors. It combines insulating layers with reflective surfaces and vapour-control functionality.
Its relatively slim profile makes it attractive for sheds, garden buildings, workshops and projects where space is restricted. It can improve comfort in buildings used regularly without requiring the thicker build-up of higher-performance products.
Choose SF6 when: budget, ease of installation and minimal thickness are priorities, and the overall insulation requirement is relatively modest.
SuperFOIL SF19BB: Best for Breathable External Applications
SF19BB is a 40mm-thick breathable multifoil product designed for applications such as roofs and external wall insulation. Its breathable outer membrane helps manage moisture by allowing water vapour to escape from the building fabric while providing resistance to external water penetration.
This makes it particularly useful when insulating timber-frame walls, roof structures or solid walls externally, where the correct moisture-management strategy is essential.
Choose SF19BB when: you need insulation combined with a breather membrane. It can simplify the construction build-up by combining two functions in one product, although the complete wall or roof design must still provide appropriate moisture control.
SuperFOIL SF19+: Best All-Round Multifoil Insulation
SF19+ is a versatile 45mm-thick multifoil insulation product suitable for roofs, walls and floors. It combines thermal insulation, a reflective radiant barrier and a vapour control layer (VCL).
It is a popular option for extensions, loft conversions, renovations and timber-frame projects where space is limited but meaningful thermal performance is required. It can be installed as part of a standalone or hybrid insulation system, depending on the building design and required U-value.
Choose SF19+ when: you want a flexible, general-purpose product offering a balance between thickness, performance and versatility. Remember that it is a vapour-control product, not a substitute for a breathable external membrane.
SuperFOIL SF40: Best for Higher Thermal Performance
SF40 is a thicker, 65mm multifoil insulation product offering greater thermal resistance than SF6 and SF19+. It is suitable for roofs, walls and floors, particularly where improved insulation performance is a priority.
Its increased thickness can make it a better choice for habitable loft conversions, extensions and energy-efficiency upgrades where available space allows a more substantial insulation layer.
Choose SF40 when you need higher thermal performance from a multifoil system and can accommodate the thickness required.
