Tyvek® Butyl Tape is a double sided butyl based sealant, used to form a moisture and airtight seal between a Tyvek® membrane and most commonly used building materials. The product is compatible with brickwork, blockwork, masonry, timber, metalwork and most plastic products. Tyvek® Butyl Tape is most effective when used under compression e.g. under timber batten and is recommended for use at perimeters, chimneys, abutments, for sealing nail penetrations and around electrical sockets.