The wall of the second-floor shed dormer was moved 3 feet back from the first-floor’s exterior wall. (This “mass-reducing” roof with integral built-in gutter was framed over the resulting exposed second-floor deck.)
The 19 1/2-foot-long rough gutter was built on the ground in two 9-foot-9-inch-long sections out of pressure-treated 1-by stock. The two trough sections were joined at the center (all seams were glued and screwed) and the completed gutter was lifted in place.
At the trellis, the roof’s edge is nearly in line with the face of the exterior wall below. The trellis’s cantilevered framing made the installation of a conventional gutter impossible to pick up the water and prevent icing on the kitchen’s slider step below.
The gutter’s downslope edge is flashed with copper.
Copper flashing is run up the rake edge of the roof and at the ends of the gutter.
Custom-built copper drop tubes were installed at each end of the gutter (at a 1/8-inch-per-foot slope, the gutter’s depth varied about 1 1/4 inches from the center high point to the outside-end low points). Here, the 1-by trough bottom was routed to plane the flashing in to the rough gutter to avoid ponding (left), then the copper flange was set in sealant (right).