Installing A Metal Roof Directly To Plywood

If a proper roof inspection isn t done the 1x4 s could be installed over rotten plywood which means the screws could pull out.

Installing a metal roof directly to plywood.

Sweep the plywood clean of all dirt and debris with a push broom. When using plywood nail it directly to the purlins and screw the metal roofing panels through the plywood into the purlins as instructed by the manufacturer. Place the first screw. Repair any rotted sections of plywood before installing the metal panels.

Add the metal panels. Do need to rack the house with sheathing on walls or cross bracing. On top of this underlayment goes a slip which protects the material from tearing as the metal roof expands and contracts with changing weather. In this installation the vapor barrier is installed on the side of the insulation nearest the interior of the building.

Installing the metal roofing over 1x4 s allows the ability to also install additional insulation under the metal roof that can t be done the other two ways. In reading online it seems wise to install a vapor barrier over the plywood to prevent condensation from getting adsorbed into the plywood from the steel roof. But it seems the condensation will affect the 2x4 strapping. Remove all unused vents pipes and protrusions.

Add purlins on top of this for venting and drainage then add horizontal purlins to mount the metal roof to. I was planning on putting plywood over the rafters and cross the rafters with a 2 x4 every 16 to secure the metal roof to. Take care the first piece is aligned precisely perpendicular square to the edge. 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.

Take your first sheet of metal and place it on the roof so that it overhangs the edge at least 3 4 in 1 9 cm. How to apply metal roofing over plywood step 1. To secure it measure it roll it out over the plywood cut it to the dimensions of the roof with a roofing or utility knife and finally hammer it securely to the plywood with 1 2 inch roofing nails. Be sure the larger edge is laid so that the small edge of the next panel will overlap it.

Epdm roofing installation faq. Inspect the plywood for damaged areas. Install the roofing screws vertically along each rib in the panel. Always begin working at the point with the longest peak to eave distance.