DATA SHEET Building Paper 410 (BS 1521 - Class B1F) TYPICAL USES Building Paper 410 is a traditional, reinforced, bitumen-bonded, kraft paper laminate, which meets the highest standard of BS 1521 materials, grade B1F. This product serves a wide range of end-user defined applications. However, typical usage for Building Paper 410 has naturally evolved over time including for example, separation layers for insulated screeds, bond breaks, temporary protection and garden buildings. Manufactured with wet-strength kraft paper and meeting the technical requirements of BS 1521 for water-proof building papers, the product utiilises polymer reinforcing scrim. TECHNICAL Moisture Vapour Resistance Liquid Water Resistance Minimum Chemical Reistance Resistant to chemicals found in plaster and cement Does not attract insects or vermin Roll Specification Roll weight Note: Other product elements of the structure must be selected to reduce condensation risk. Upper Temperature Stability 1. ‘Breathing Wall’ - Vapour Control Membrane • Building Paper 410 (B1F) Moisture vapour transmission properties will allow controlled passage of moisture from room side to outside. • ix Building Paper 410 (B1F) to stud work using nail/staples, with 150mm taped F overlaps before injecting insulation. 2. Separation Layer • Allow 150mm overlaps (sealing laps is unnecessary). • Lay Building Paper 410 (B1F) above insulation to prevent wet screed soaking into insulation.