Metal Joints Oversized, Heavy Gauge Metal construction joints can be used for expansion joints, waterstops, weakness or control joints in concrete or masonry. They can also be use in formwork to create reveals and drip edges on formed concrete surfaces. Heavy-duty special keyed floor slab joints available in 31�2- in. minimum height and 16-in. maximum height. Mill galvanized is the most frequently specified finish, but stainless steel and copper are available for use in corrosive environments. Heckmann Building Products Inc.; 800/621-4140; www. heckmannbuildingprods.com