Metal Roof on Ski Cabin in Idaho Proves Challenging & Rewarding
by Brad Baker, Professional Roofing, Bellevue, Idaho, & WSRCA senior vice president
What happens when Vermont stone farmhouse architecture is crossed with Idaho ski cabin construction? If the architect is Rick Joy from Tucson, Arizona, the result is an award-winning house in the 2014 Architectural Record. Built by Schuchart/Dow of Ketchum, Idaho, for a retired business couple wanting to enjoy family and friends in their own Sun Valley ski home, the project took many hours of discussion and planning with the architect, contractor, and subcontractors. The project called for metal clad skinned roofing and siding panels aligned in a vertical pattern to give the look of metal running from the walls right thru to the roof and on up.
Schuchart/Dow called Professional Roofing, Bellevue, Idaho, to see if we were interested in bidding on the local project. We came recommended from our past metal projects in the Sun Valley/Ketchum area, especially the copper panel project for the Sun Valley Company’s symphony project. The symphony project, done in 2008, had 18″x36″ copper panels; whereas the Sun Valley ski house project called for 16″x30″ zinc panels. After numerous meetings discussing design, cost, and time of installation, the team decided on 22-gauge Kynar® metal for the gray zinc look and the strength needed for the 120# local snow conditions. After reviewing several sample colors, the architect selected Metal Sales of Spokane, Washington, for its mystique soft gray color.
Once Professional Roofing was awarded the project, the fabrication process of the panels started. The house would need 1500 panels for the siding and 2500 panels for the roofing. When discussing the design and cost, the architect agreed on a panel size that would be cost effective for the size of flat sheets ordered. Professional Roofing was able to take a standard 4’x10′ sheet and cut it into 16″ widths and 30″ lengths; thereby getting 12 pieces per sheet with no waste. The finished panels ended up being 13″x27″ and were held in place with 24-gauge break-formed stainless steel clips. The top clip was 8″ wide on the 13″ width side and two 4″ wide side clips were used on the 30″ length. With all the hand braking of 4,000 panels, it was clear that using the 10′ brake or the 4′ and 6′ box/pan brake wouldn’t be very efficient with two people. Years ago, at a zinc-forming class I attended, they had demonstrated a brake that could be used by one person to form the panels. Both the operator’s hands could be used to adjust the panel at the brake and then take their foot and clamp the panel. Tom Evans at Benoit Sheet Metal Equipment out of Seattle, Washington, was contacted about this brake and he said, “That brake is called a Schechtl Model UK-125/S hand-operated folding machine.” The next challenge was getting one of these brakes. They are made in Germany and only ship once the order has been placed and payment received. Needless to say, the four-week lead-time was worth it. All the panels came out nice and clean and there were no folding dings in the panel corners that can happen with other brake style fabrication.
Before installation of the metal roof panels, Professional Roofing installed Grace’s Ice and Water Shield® HT over the plywood decking. Next, a layer of 30# felt was installed to protect the Ice and Water Shield during the cold-roof installation of 2’x4′ flat sleepers and additional plywood shear. The cold-roof application was used not so much for heat loss but as a back up for the low pitch of some of the roofs. The roof area was made up of basically two wings with a flat deck intersection between the two. The two metal roof wings have slopes ranging from 1.5:12 to 4.5:12 and the slopes don’t necessarily run from top to bottom but can run left to right depending on the low points at the eaves and the high point at the ridges. When laying out the roof panels, it was important to make sure that the winter snow movement wasn’t bucking the panel seams. Some areas were so hard to tell which direction the roof was actually sloping that we used the white milk jug trick where we took a gallon of milk and slowly poured it over the black Ice and Water Shield to see which direction the milk ran and thus determined the slope of the roof.
After the cold-roof plywood was installed, another layer of Grace Ice and Water Shield HT was installed, followed by GAF’s VersaShield® fire-resistant roof deck protection for a UL Class A fire assembly, then Colbond’s Enkamat® 7010 roof underlayment, used for its thermal and acoustic break qualities before finally installing the 22-gauge roof panels. With so many roof panels, string lines were used from top to bottom to be sure the lines were kept straight, so the wall panels lined up with the roof panels. Most days there were only a crew of two or four men installing panels. Needless to say, the general contractor always felt there should have been more. Professional Roofing focused more on the quality of the installation than the quantity of panels installed in a day.
Part of the construction process was the cold-roof application. Professional Roofing installed both layers of Grace Ice and Water Shield, and the general contractor installed the 2’x4′ sleepers and plywood. Originally there were five 18″ diameter mechanical pipes coming thru the roof. Early on in the construction build, we flashed the five flue pipes, but when we returned 40 days later after panel fabrication, there were now six pipes. No big deal, until we found out that the general contractor hadn’t sealed the flue at the cold-roof plywood and when powder snow got in thru the ridge screen vent, there was a small leak at the pipe. Luckily, we were able to lift the plywood and reseal the lower layer of Grace Ice and Water Shield before the zinc panels were installed. Here again, just like the overall project, it wasn’t about how fast the project moved but more about the quality of work being done and that the work was done correctly. The end result for everyone on the job was when the general contractor emailed that this team project had been chosen as one of the eight Record Houses for 2014 as awarded by Architectural Record. This project architecture was a first for the ski-resort area and the award speaks for itself on design and quality of work.