The use of highly durable sealants and fasteners is a detail that separates an excellent metal roof contractor from a merely adequate one. For areas where mechanical fasteners are exposed (e.g., in exposed fastener panels), the contractor must use high-quality screws with large, UV-resistant neoprene washers that compress properly to form a watertight seal without cracking the metal. ... https://kkroofspecialist.com.sg/metal-roof-contractor/