One Way To Install
Above: Old box gutters were removed from this roof perhaps 20 years prior and covered over with asphalt shingles, now crumbling. The PA black slate on the remaining roof, however, is still quite good, despite the installation year of 1878. It's probably Cathedral Gray slate.
Above: Crumbling asphalt shingles are removed to expose plywood underlayment. The roof now has some plywood decking and two different slopes, which complicates matters.
Above: Shop fabricated 20 ounce copper drip edge.
Above: Note that we installed a 2x4 at the top of the plywood by nailing it directly to the roof sheathing with 16 penny nails. This allows us to cleat the standing seam pans to the 2x4 rather than the plywood. It also lifts the pans off the plywood, eliminating the need for rosin paper. The 2x4 acts as a bridge to support the back of the 36 inch long standing seam pans. Every situation is different and sometimes some creative thinking is necessary to get things to work. This technique worked well for us here, but may not work elsewhere. Note that we did not use any underlayment under these pans. We're certain they will not leak. Note that the valley copper is fitted with long cleats that are riveted and soldered to each side. This allows us to attach our standing seam pan to the valley.
Above: Pan is attached to right side of valley by clamping to valley cleat. Left valley cleat is soldered in place and ready for left pan. The pans are fabricated from 24 inch by 36 inch 20 ounce partially hardened copper. The valley section is 24x48. The pans are done in the standard double lock standing seam style with a 3/4 inch fold at the bottom of the pan to allow for clamping onto the drip edge. There is a 1/2 inch fold at the top to allow for cleats. The sides are also cleated. See below or refer to the SMACNA manual for details.
Above: The standing seams are double locked.
Above: The 20 ounce, partially hardened copper is very rigid and durable. The finished job should last the lifetime of the roof owners.
Above: Here's where the fun starts. We have two valleys meeting at a point with a gable *and* a hip juncture at one side of an octagonal dormer. We lock-seamed and soldered a custom-made 20 ounce copper piece at the bottom of the two valleys. This single piece, made up of 6 individual pieces soldered together, clamped at the bottom over the fabricated drip edge. Then...
Above: ....we finished the right edge with a standing seam fold, and continued our standing seam panels around the octagonal dormer. Each hip on this dormer had to have two standing seam panels custom made (one on each side of the hip) with both an angle cut to align with the hip and a standing seam on the hip at the angled edge.
Above: Another look at that custom piece.