Tower Sealants TOWER TECH forms a permanently flexible, airtight, water-resistant seal in gaps up to 2 in. wide. Tower Tech also offers 50% total joint movement, is UV and mildew resistant, and is VOC compliant in all 50 states. TOWER TECH caulk is internally plasticized resin requires no mixing or priming to bond to most materials, including concrete, wood, and masonry.