To guarantee air and wind-tightness for the skin of a construction it must have the appropriate foils or panel materials providing a permanent seal at overlaps, gaps, joints and penetration points. BUTYL Dehnflex - Stretch Flex is used particularly as a seal at penetrations points for wind seals, vapour barriers, roof underlays and OSB. Due to its great flexibility the tape can easily be positioned around the openings that require sealing and neatly pressed down. Its extremely good adhesive properties permit work on a variety of substrates mostly without a primer.