Polyguard Blue Barrier Gap Filler (BBGF) is a structural adhesive and detail sealant that provides a watertight, flexible seal for a variety of applications, including filling structural wall substrate voids and cracks, bonding dissimilar structural wall substrate materials at seams and joints, sealing as a sheet membrane top termination protection, and providing an exposed sheet membrane edge sealant. BBGF is made with Silyl Terminated Polyether (STPE) technology, which gives it superior adhesion to a wide variety of substrates, including wood, metal, concrete, and masonry. It can also be applied in wet or dry conditions, making it ideal for a variety of construction projects. BBGF is durable and long-lasting, even in harsh weather conditions. Whether you are a professional contractor or a DIY homeowner, Polyguard Blue Barrier Gap Filler (BBGF) is the perfect solution for creating a watertight, flexible seal for a variety of applications. Material: Plastic.