To improve energy performance in buildings, DuPont has launched a new vapour control layer for airtightness. Offering adaptability to changes in humidity levels thanks to the widest vapour resistance span (0.26 MNs/g to more than 150 MNs/g) on the market, DuPont AirGuard Smart is suitable for both roof and wall applications, says the company. This airtight membrane has been developed for new build and refurbishment projects and is specifically designed for renovating roofs from the exterior.<br> <br> DuPont claims that DuPont AirGuard Smart has superior properties thanks to the extreme span of sd-values which allows maximum protection against structural damage. It adapts to changes in humidity levels and minimises or increases the water vapour transmission rate, as needed. It combines a drying-out and vapour control function in one layer. Applications include above rafter insulation or between rafter insulation, but it can be also used in dry lining applications from the inside.