Flat Roof Sheathing Installation

How to correctly install plywood or osb roof sheathing.

Flat roof sheathing installation.

Position the first piece of plywood or oriented strand board sheathing on the bottom edge of the rafter tails at one end of the roof. Snap a chalk line down the line of the rafters on the piece of plywood so you can find the rafters with your nail gun. You mentioned in another article on gba that venting the top side of sheathing with a cold roof steel roof fastened on battens allowing air flow directly underneath the roofing but on top of the sheathing while at the same time venting underneath the sheathing is incompatible. Yet for historic modern style buildings like this old house s cambridge tv project flat roofs are at the core of the architecture meant to reflect the broad horizontal lines of the natural landscape.

Avoid installing osb with the textured side down. Of course you don t need to live in a modern house to deal with a flat roof. Be sure the larger edge is laid so that the small edge of the next panel will overlap it. Flat roofs aren t architecturally logical as rain and snow will shed much more quickly off a sloped roof.

So even though flat roofs are ideal for drier landscapes in climates with heavy precipitation a properly installed flat roof can be a fine choice for a homeowner especially thanks to ever improving waterproof materials and installation techniques. Align the long edge of the sheathing with the ends of the. Align the first metal roofing panel so that it overlaps the edging by 1 2 to 3 4 of an inch and is square to the roof line. Avoid putting osb on wet roof trusses.

Install osb textured side up. Nail the plywood around the top outside and bottom edges every 6 inches. The textured surface helps flashing and waterproof underlay stay in place effectively.