Prefabricated Edge Metal Helps Shape Unique Roofs on a Georgia Hospital

3-D PUZZLE

The project’s design included a “sail” wall with a half-moon radius façade in the front of the new patient tower. In addition to being curved, the sail wall is slanted, ranging from 3-feet wide down to 16-inches wide. After the blocking and skin were installed, Diamond Roofing dried the sail wall in and brought its supplier, Commercial Roofing Specialties, onsite to help with exact measuring. “With the radius and the slant, the sail wall changed dimensionally every inch,” Mossige recalls. “We literally rolled red rosin paper over that wall and traced the curve of the sail. Then we sent the paper to the manufacturer to use as a template and lay it out to make the edge metal in the shop.”

The finished edge metal was shipped in 4-foot sections, and Diamond Roofing had to put the pieces of the puzzle together. To make matters more challenging, the sail wall was also higher on the 3-foot side and lower on the 16-inch side. Because upper pieces have to be on top of the lower pieces to prevent down-flowing water from entering the system, the team had to start at the lowest point and shingle-in the coping cap working upward.

In some areas, the distance between the building and sail wall wasn’t wide enough to set up a ladder. “Without access to the back side, we had to tie-off at the top of the sail wall and straddle it to fasten the cleat and set the coping cap in the saddle,” Mossige recalls. “With that slanted, curved and sloping surface, we were basically 100 percent tied-off and riding the wall like a horse.”

To ensure safety throughout the project, Brasfield & Gorrie led a pre-job start-up safety meeting. Where parapet walls were less than 39 inches, the contractor temporarily extended those roofs to 48 inches to protect the multiple trades working on them. When working on any canopies, Diamond Roofing’s team had to be tied-off with a safety harness and a retractable lanyard.

BUTTONED UP

Some walls were 38-inches wide, which demanded the coping follow suit. Large coping is difficult for crews to handle high up in the air and when dealing with wind forces. Moreover, the wider the coping, the greater the chance for cupping (dips in the metal) to occur. To guard against cupping, the team had to install the saddles closer together at 2 foot on-center and install more cleats than on a standard coping.

Despite the various construction constraints, the 18-month project did not disrupt hospital operations. “The architects designed all the curves and unique walls to make the campus beyond ordinary and give the hospital a certain appeal,” Mossige says. “And, honestly, I enjoy the challenges.”

Team

Roofing Contractor: Diamond Roofing Co., Atlanta
General Contractor: Brasfield & Gorrie, Atlanta
Supplier: Commercial Roofing Specialties
Architect: Gresham Smith and Partners, Atlanta

Roof Materials

Prefabricated Edge Metal: OMG PermaSnap 2 Coping in Redwood and Surrey Beige from OMG EdgeSystems
Edge-metal Kynar 500 Coating: Arkema
Polyisocyanurate Insulation, Cover Board, SBS Modified Bitumen and Foam Adhesive: Johns Manville
Reflective Roof Coating: TopGard 5000 from Johns Manville
Air Barrier: ExoAir from Tremco Commercial Sealants & Waterproofing

PHOTOS: OMG EDGESYSTEMS