All Therma-quilt glass fibre insulation supplied as part of the Twin-Therm® roof and wall cladding system has every fibre coated with silicone to prevent moisture retention. It is CE Marked and complies with the Lambda 90/90 whilst achieving zero ODP and zero GWP.
Glass fibre and rock fibre insulation traps air and it is this action which delivers the thermal performance. Air can move in and air can move out, but the thermal performance cannot change.
For further help and advice please see the following Technical Information Papers (TIPs)