The process started with the removal of the old roofing membrane and some rooftop demolition. For most large roofs like this, there would be multiple access points and the rig would be relatively simple. In this case, because of the shape of the layout, there was really only one access point to the top of Building 64, and it had an obstructed view to the ground below. A 50-foot scaffold tower was erected to get the crew and equipment to the top. When it came time for the crane work to be done to assist with demolition, there was no line of vision between the operator and the material being demolished and the people directing the action from above. Expertise and trust came into play as the crew on the roof used walkie-talkies to guide the crane operators to success.
Once the previous membrane was removed, there was some obvious decay to the concrete on the roof, so Cleveland Building Restoration was called on to work on the masonry work so that the membrane could be installed properly.
The surface below the membrane is, in essence, a layer of concrete. A temporary membrane was used to protect that concrete against weather damage while the permanent membrane was being put in place.
Nate selected a fleece-backed PVC membrane from Johns Manville to complete the project. This is a waterproof membrane that has a 3.5-in. thick installation with a 1/2-in. thick gypsum board backing called DEXcell® that acts as a cover board. This board’s high density improves uplift pressures from high winds to reduce the likelihood that Cleveland’s notorious winter winds would damage the membrane.
The temporary membrane isn’t removed as part of this process. The permanent membrane was torch fused with a hot roll of asphalt that was 3 ft. wide and 30 ft. long, using the temporary membrane to increase waterproofing on the concrete surface. The process was sealed with a two-part polyurethane adhesive. The seams of the permanent membrane were then heat welded with a LEISTER heat gun to complete the sealing and further protect against water damage.