For someone very used to the process of installing composition shingles, the installation of the new roof using different techniques seemed well worth paying attention to.
In addition to the basic roof installation, I also opted to have the trim around the dormers wrapped in steel to further reduce future maintenance needs, dormer gutters removed (they were nearly impossible to keep clean and only seemed to serve as water reservoirs and latrines for the local raccoon population), and the old center chimney which had not been serviceable for many years knocked down below roof level.
The actual installation began with the removal of the chimney and decking over the resulting hole, then removal of the existing ridge cap, drip edges, and the dormer gutters. The remainder of the existing roof was swept clean, then covered with a breathable radiant barrier underlayment.
2×2 battens spaced for the panels were screwed to the decking. Panel installation began from the top and worked down. Panels were installed by lifting up the covering panel enough to slide in a panel to the top bend location and drive screws perpendicular to the roof into the top batten. The top panel was then pushed down on top of the lower panel and screws were driven parallel to the roof through both the top and bottom panels into the batten, which effectively interlocks the panels. This does result in an exposed screw, however in most spots the panel is designed with a “gutter” over the parallel screw location and the screws are gasketed, which combine to prevent leakage. The exposed screws are also color matched to the panel so they blend in visually.
Most flashing was done simply by flattening a section of the panel and bending it to the required angle, then covering with either the existing siding or a new piece of solid colored steel.
When it was time to do the standing seam on the porch roof a panel bending machine was brought on-site and the panels made directly to measure from a roll of coated coil stock and the ends hemmed by hand.
The panels were secured with clips screwed through the deck, then each panel was crimped to the next panel to create an externally seamless roof. For maximum energy efficiency the standing seam panels could have also been mounted on battens to provide an airspace, but as they were only installed on the exterior porch roofs I opted for them to be installed directly over the old roof without battens.
Installation was completed by wrapping the dormer fascia and completing the remainder roof trim.
In summary, it took a crew of 4-5 experienced installers nearly a week to complete the job. 1 day was rained out, 1 day was cut short by rain, but the other days they worked nearly 12 hours each day to complete the job on schedule. I was very pleased by their work ethic; they worked hard and accurately, took great care to keep the worksite clean and safe, and were as unobtrusive as possible for the work they were doing.