Copper has been used as a construction material for centuries. During this time, it has achieved an excellent record for low maintenance and durability. Proper design and construction are essential to ensure high quality, long-lasting installations.
This section contains details and descriptions of the basic components commonly used in sheet copper construction. These include various seams, expansion joints, edges, hold-downs, and cleats.
There are three methods to fasten copper to a substrate: cleating, nailing, and screwing. All fasteners should be of copper or copper alloy, such as brass, or bronze, except for washers and expansion shields, which are of lead, bronze, rubber, or plastic. Fasteners of a neutral stainless steel alloy are also acceptable.
This is the most commonly used method, because it allows the copper to move, minimizing the potential for buckling. Cleats are usually made of 16 oz. copper, although they need not be heavier than the material being secured. Cleats made of compatible stainless steel are also acceptable. Two types of cleats are used. Fixed cleats allow a small amount of movement, while expansion cleats typically allow up to 3/4" total movement. Fixed cleats are usually suitable for short pan construction. Long pans require the use of expansion cleats, see Roofing System - Long Pan. Cleats are typically spaced at a minimum of 12" on center.
This method is predominantly used where movement is not desired, such as at a base flashing at built-up roofs, gravel stops, and eave strips. Nailing is used only on cleats and copper strips up to 12" wide. Only one edge of a strip should be nailed, to allow movement perpendicular to the line of nailing. Nails should be spaced no more than 3" O.C. to provide continuous resistance to thermal stresses. All nails should be flathead, wire slating nails, at least 1" long, of not less than 12 gauge hard copper, brass, or bronze. Those used in wood should be barbed; nails used in concrete or gypsum should not. Surfaces with poorer nail-holding qualities require longer, stronger nails. For the right nail to use with such material, contact the manufacturer.
This method is used where the copper must be held rigidly in place, such as at a ridge cap subject to the severe vibrations caused by wind, or as a hold-down for large, flat copper areas. It is also used to secure copper to masonry when expansion shields are required. Screws should be made of stainless steel, bronze, or brass. They should have round heads, and flat seats which will not puncture the copper. Lead washers may be used for additional protection. Where watertightness is required, a small copper cap is soldered over the screw head, see Typical Copper Hold-Downs, Detail B.