How to Fasten Plywood to Steel Roof Trusses
Steel roof trusses or rafters are made from thin sheets of steel that have been formed into a "C" shape. It's the shape that gives them their strength while allowing them to be lighter than traditional wood trusses. Attaching building materials to the metal trusses requires special fasteners that can be drilled into the steel, so traditional wood-screws will not work with a steel-truss roof. For residential installation you should use at least 3/4 inch plywood. Does this Spark an idea?
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Things You'll Need
- High torque drill (cordless drills are not recommended)
- Wood-to-steel screws
- 3/4 inch plywood
Instructions
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1
Measure the distance between your trusses. You must have the joint between two pieces of plywood land in the middle of a roof truss. If necessary, cut your plywood to the right length to make your joints line up with the trusses. The plywood should lay across the trusses so the grain of the plywood is perpendicular to the trusses, so make your cut(s) accordingly.
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2
Slide your plywood into place across the trusses. Starting at the bottom of the roof, lay your first piece of plywood all the way to one side (the bottom corner). Screw through the bottom corner of the plywood into the roof truss. Line up the top corner of the plywood carefully so that it is square with the trusses and screw in the top corner.
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3
Place screws every six inches on the outside truss and every 12 inches on the inside truss. Butt your next piece of plywood up to the first one and screw it in with screws spaced 12 inches apart until you reach the opposite edge of the roof (then use another row of screws six inches apart).
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4
Continue installing the plywood sheathing in rows up to the ridge of the roof.
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References
- Photo Credit new house roofing image by Gale Distler from Fotolia.com
