This type of roof is a formed steel sheet coated with a lead-tin alloy. It is most frequently applied over sloping roof structures in a flat, standing or batten seam method by hand or machine formed. When applied in rolls, the flat seam method has flat locked and soldered joints normally held down with cleats. The standing seam method can be applied over sloped roof surfaces with the seams being finished and standing about 1" high. Batten seams are formed with the use of a narrow strip of wood that forms the seam. Normally the seams are unsoldered with the joints being staggered. The spacing of the seams is characteristically a function of the architectural design of the roof.