Thermafleece Breather Membrane is a lightweight vapour permeable underlay designed for use on floors and walls or on top of insulation as a protective layer. It comprises 3 layers; two outer layers composed of a non-woven polypropylene and an inner breathable microporous film. Thermafleece Breather Membrane is ideal for supporting insulation between suspended floor joists or as a protective layer above insulation installed between floor joists to prevent the accumulation of debris on top of the insulation. The membrane can be nailed or stapled to the underside of the floor joist if access permits. Alternatively, the membrane can be installed from above the rafter.