The most common ways of making architectural sheet metal joints watertight are through the use of sealants or solder. While sealants can provide watertight integrity on steep-sloped applications, the relatively short service life of sealants, when compared to the expected service life of sheet metal, make them an unreliable choice for assemblies that must rely on long-term watertight integrity of the joints to prevent water intrusion. This is especially critical in low-slope applications where water may linger or pond on the surface of the sheet metal. Since most architectural sheet metal components are formed from materials of less than 1/16-inch in thickness, the joints cannot feasibly be welded and must be joined with solder. Read More.