Vapour control & condensation
Nexseal LE meets the requirement of one perm or less for a Class II vapour retarder (per ICC / ASHRAE) when installed at 40.6 mm depth, with a declared water vapour resistance factor of μ 62 (BS EN ISO 13788:2012). Interstitial condensation risk should be assessed for the specific construction, designed to the relevant parts of BS 5250:2021; an air and vapour control layer (AVCL) may be required.
Fire performance
The foam is classified Class 1 to BS476 Part 7, and Class A to ASTM E-84 (UL723) with a Flame Spread Index below 25 and Smoke Developed Index below 450 at 4" thickness. In habitable spaces an approved thermal barrier may be required — building regulations and the building's fire strategy govern this on each project.
Service & environment
Designed for ambient service temperatures of -40°C to 82°C (104°C intermittent). It is a low-VOC material compliant with the California Department of Public Health (CDPH) Standard 01350, referenced by CHPS and LEED — suitable for sensitive environments such as schools and healthcare facilities. The closed-cell structure self-bonds to the substrate as it cures, with no mechanical fixings.
