Novia 500 VCL is a low-cost, blown polythene material, suitable for use as a vapour control layer within the walls of timber frame constructions, or where control of the passage of water vapour is required. Vapour Control Layers (VCLs) are used to manage the transition through the building envelope of naturally occurring moisture vapour, which is produced by general building use. Our range of VCL membranes are formulated with a wide variety of construction designs in mind, delivering specific solutions for various applications and requirements. This product also performs the additional function of an air-leakage barrier, to prevent losses due to unwanted convection flows. We advise the use of Novia compatible butyl and foil sealing tapes to ensure a complete barrier integrity throughout the entire life of the product. Novia 500 VCL should be used in combination with Novia breather membranes to provide an air-tight and vapour resistant system. Novia 500 VCL is fully CPR compliant and is CE Approved to EN 13984:2013. Properties Length: 50m. Width: 2.7m. Roll size: 135m2. Roll weight: 15.5kg. Water vapour resistance: at least 250 MNs/g to EN 1931. Material: virgin polythene. Material thickness: 500 Gauge / 125 Micron (nominal). Colour: clear with green tint. CE Approved: to EN 13984:2013. Application Novia VCL products are sealed using one of our double-sided butyl tapes, generally using an overlap of 75mm to 100mm, but with certain products we do state that a larger overlap is required. A lap-seal is then applied on top using one of the foil tapes. The wider the tape used, then thestronger the seal will be, so choose a tape based on your own particular application and budget. We also suggest that in order to improve overall airtightness, butyl tape is preapplied to any studs or timbers at the points where fixing is to be made. By preparing the fixing point in this way, when staples etc are applied to either the membrane itself or the final wall covering such as plasterboard, then the achieved seal will be far better.