Kalzip VCL - Vapour control layer Technical Information TIS-COMP-VCL-039 6 June 2019 – Issue 7 Kalzip VCL - Vapour Control Layer Introduction It is good practice to enhance the performance of a roofing system by incorporating a high performance vapour control layer. A vapour control layer will restrict the movement of water vapour from inside the building into the roof construction, thereby minimising the risk of condensation and also assist in limiting air permeation through the system. The vapour control layer should always be installed on the warm side of the construction and should be continuous across its surface. It must be fully sealed at all laps, perimeters and penetrations in order to ensure its effectiveness. The type of vapour control layer to be specified would be dependent upon the use of the building and therefore the condensation risk. Air-tightness of a building is covered under the Building Regulations for England and Wales Approved Document L, and the Building Regulations for Scotland Technical Standard Part J, and using a vapour control layer can be used to enhance the performance of the roofing system. Specification The vapour control layer for the Kalzip Roofing System is to be Kalzip VCL or Foil supplied by Kalzip Limited. The vapour control layer is to be lapped by a minimum of 50 mm and sealed with one or two layers of Kalzip VCL sealant tape. See attached table, Recommended Kalzip vapour control layer for Kalzip roofing and cladding systems.

Storage and handling The rolls of Kalzip VCL vapour control layer material must be handled carefully to avoid puncturing and to prevent damage and must not be stored on end. For long-term storage the rolls should be protected from ultra-violet light indoors and under non-translucent covers. Installation The Kalzip VCL vapour control layer should be laid dry and should be completely sealed around all roof perimeter edges and upstands of roof penetrations. The vapour control layer should be lapped a minimum of 50 mm and continuously sealed with the Kalzip VCL sealing tape. Kalzip Liner Roof System...

Recommended Kalzip vapour control layer for Kalzip roofing and cladding systems Humidity Class3 Typical Building Type Kalzip VCL1 Liner/Decking Configuration Solid Liner Perforated Liner Sheet & Solid or Perforated Decking Storage areas Kalzip VCL with one row of Kalzip VCL sealing tape2 Kalzip VCL with one row of Kalzip VCL sealing tape Offices, shops Kalzip VCL with one row of Kalzip VCL sealing tape Kalzip VCL with one row of Kalzip VCL sealing tape Dwellings with low occupancy Kalzip VCL with one row of Kalzip VCL sealing tape Kalzip VCL Foil with one row of Kalzip VCL sealing tape Dwellings...