These amendments came into force on 21 December 2018 and of particular relevance to membrane specifiers and installers is a clarification to Regulation 7, which requires most components used in external walls over 18m to meet Euroclass A1 or A2.
Use of membranes as part of the external wall construction: 12.14 Particular attention is drawn to the following points. a. Membranes used as part of the external wall construction should achieve a minimum classification of European Class B-s3, d0.
This clarification is due to the complexity of manufacturing a noncombustible membrane which is still vapour permeable. Some European membrane products which quote A2 ratings do not breathe sufficiently to comply with BS5250, meaning using these membranes in the UK climate could make the building unhealthy and result in a much greater risk of condensation issues and mould growth.
Incorporating Wraptite® in the Design Makes Sense
• Complies for use on buildings over 18m under 2018 Part B amendments with Wraptite at Class B,s1,d0*
• Included within BS8414 testing with cladding manufacturers • EPDM not needed to the frame of the building
• Less EPDM required at window details
• Easier detailing for corners, openings and movement joints
• Hygrothermal Modelling (WUFI) will identify whether the construction requires a VCL. In some instances, a VCL may be unnecessary, meaning easier a quicker install of dry lining package
• Improving airtightness may allow changes to thickness or type of insulation used when modelled through SAP or SBEM
• No need to tape sheathing boards as Wraptite is positioned across the whole board
• By using Wraptite externally, a wind and watertight envelope can be achieved faster, with the outer cladding removed from the critical path. This allows internal works to begin earlier.
Fireshield® - a vapour permeable membrane with a fire proof surface Fireshield is the culmination of leading research to produce a vapour permeable membrane with a fire proof surface, its unique intumescent composition actively reacts to prevent fire taking hold. Fireshield complies with BS5250, BS4016 and NHBC requirements for vapour permeable walling underlays. It is installed and fixed to the substrate in the same manner as standard breather membranes using mechanical fixings. Applications include both commercial and residential buildings including apartments and student accommodation, as well as rainscreen cladding and applications over 18m high.
• Fire proof surface – unique intumescent composition actively reacts to prevent fire taking hold
• Vapour permeable walling underlay for use either directly onto sheathing or insulation
• Class B, s1-d0 but performs differently to other similar class products
• Complies with BS5250, BS4016 & NHBC requirements for vapour permeable walling underlays
• Suitable for applications over 18m high.
*tested over 12mm calcium silicate board/fibre cement board as per BS EN 13238:2010. All tests carried out to EN 13859-2 standard.
