SuperFOIL SFBB Reflective Breathable Membrane – External Breather Membrane + Radiant Barrier (2-in-1)

SuperFOIL SFBB is a breathable, reflective membrane designed for the external side of roofs and walls, whereas SuperFOIL SFTV is a reflective vapour control layer (VCL) intended for the internal (warm) side of the construction.
This distinction makes SFBB suitable for applications where moisture vapour must escape safely while still benefiting from reflective thermal performance.

SuperFOIL SFBB is part of SuperFOIL’s reflective breathable membrane range, providing a 2-in-1 solution: a breathable external membrane combined with a radiant barrier in one ultra-slim product (nominal thickness < 1 mm). It is ideal for new build and retrofit roof and wall build-ups where breathability, moisture safety, and weather protection are required.

Product Dimensions & Weight

• Thickness: < 1 mm (0.41 mm)

• Length: 25 m

• Width: 1.5 m

• Weight: approx. 5.4 kg

2-in-1 Multifunctional Design

SuperFOIL SFBB combines two key functions in one product:

• Reflective breathable membrane (breather membrane function)

• Radiant barrier that reflects radiant heat when installed adjacent to an air space

This reduces the need for separate layers while simplifying detailing and improving overall build-up efficiency.

Breathable + Watertight External Membrane

SFBB is designed to protect roof and wall structures from both rain penetration and condensation risk:

• W1 watertightness rating – functions as a secondary rain barrier

• Breathable membrane performance – allows moisture vapour to escape, reducing the risk of condensation, mould, and damp

• Designed for use on the external side of roofs and walls

This makes SFBB particularly suitable for timber-frame and moisture-sensitive constructions.

Thermal Performance

SFBB’s reflective performance is achieved when installed adjacent to an air space (for example, a cavity or service zone), where the radiant barrier effect provides measurable thermal benefit.

Certified thermal performance (EN 16012 methodology):

• Roof (incl. air spaces): 0.29 m²K/W (R-Value)

• Wall (incl. air spaces): 0.36 m²K/W (R-Value)

• Floor (incl. air spaces): N/A

• Emittance: 0.19

What does R-Value mean?

R-Value (m²K/W) measures resistance to heat flow.
The higher the R-Value, the better the insulation performance.

What does Emittance mean? (important for SFBB)

Emittance measures how much heat a surface emits (radiates).

SFBB has a higher emittance (0.19) than classic reflective vapour control layers (typically around 0.05), meaning slightly lower reflectivity.

This is expected, as SFBB is a breathable membrane designed to allow vapour movement while still providing effective radiant heat reflection when installed with an adjacent air space.

While its reflectivity is lower than low-emittance foil layers, it provides the essential balance between breathability and thermal performance.

Water Vapour Control Performance (Breathability)

• Water vapour resistance: 0.115 MN·s/g

This low vapour resistance supports breathable external constructions, helping moisture escape safely from the build-up and reducing condensation risk.

Key Benefits

• Breathable external membrane with integrated radiant barrier

• W1 watertight secondary rain barrier

• Supports moisture escape and reduces condensation risk

• Lightweight, flexible, and easy to handle

• Simple installation with minimal waste

• No specialist tools required

• Suitable for new builds and retrofits

• Manufactured using up to 40% recycled materials (range claim)

Applications

SuperFOIL SFBB is suitable for use in:

• Roofs (external side)

• Walls (external side)

It is especially effective when installed adjacent to an air space to maximise reflective thermal performance.

Fire & Safety Performance

• Reaction to Fire (Euroclass): Class F

SFBB – Quality & Certification

• Manufactured under a certified ISO 9001:2015 quality management system (manufacturer level)

• CE marked with Declaration of Performance

• Conforms to:

  • EN 13859-1:2014 (flexible sheets for roof underlays)

  • EN 13859-2:2014 (flexible sheets for walls)

• Rated W1 for watertightness (secondary rain barrier)

• Tested to support compliance with current building regulation requirements when installed correctly

Why Choose SuperFOIL SFBB? (B2B Perspective)

SFBB is specified where an external breathable membrane is required but the project also benefits from reflective radiant performance. It supports moisture-safe detailing on roofs and walls while simplifying the external build-up by combining breather membrane and radiant barrier functions in a single ultra-slim sheet.

SuperFOIL SFBB & Recommended Accessories

Summary

SuperFOIL SFBB is a breathable, reflective membrane designed for the external side of roofs and walls, providing a W1 secondary rain barrier, moisture-safe breathability, and radiant barrier performance in a < 1 mm solution. It is an ideal choice for modern timber-frame and retrofit constructions where condensation control and weather protection are critical.