Grade A1F building paper is a bonded kraft paper laminate with bitumen which is durable and moisture resistant. It conforms to BS 1521 standard. A1F is widely used as a lead underlay, as it provides a separation layer between the lead sheeting and the substrates below, preventing alkali attack from drying cement or concrete whilst allowing for thermal movement of the lead sheet. BS1521 Grade A1F, bitumen bonded and laminated for strength Uses: Ideal for smooth surfaces like vented plywood, natural stone, concrete, or screed It can be used as a Vapour check layer A temporary roof covering A damp-proof membrane (DPM) for timber floors An underlay for uninsulated cladding.A1F Building Paper is 1m wide. Order in increments of 1 metre up to 5 metres, then 10, 15 or 20 metres. A1F Building Paper has a width of 1m. Also available in a 25m roll. Information Sheet for Building Paper
