Insulation for under window & door sills


Doors and windows form part of a building’s thermal envelope. Positioning them within their openings to achieve continuity of insulation can be a detailing challenge, making it more likely that the edges of the opening act as a thermal bridge - particularly at ground level below a door or full-height window.


Where doors and windows do not line up with surrounding wall insulation, masonry can allow heat energy to bypass the thermal envelope. Providing sufficient insulation where a floor screed or slab meets a door or window cill is difficult - especially where level access requirements through a doorway mean there is no step into the building. As a load-bearing insulation element, PERINSUL HL is the perfect solution to the thermal bridge.

Downloadable documents

      system characteristics

      • Proven concept: full suite of calculated and accredited details, including psi values, available for common applications featuring a structural thermal bridge.

      • Energy efficiency: reduces building heat loss and space heating demand.

      • Load-bearing: strong and unique insulation element, capable of bearing structural loads.

      • Healthy living: elimination of heat loss at ceiling edges prevents ‘cold spots’.


      how to install perinsul hl

      under window and door sills

      legal notice

      about PERINSUL products

      The information relating to the products and systems contained on this website is provided in good faith and for general information purpose only. Such information is in any event subject to our product’s legal notice, the content of which users are invited to acknowledge under the following link: Legal Notice