Metal Roof Over Osb

Osb is widely used as roof decking material.

Metal roof over osb.

Metal roofing roofing answers roofing installation roofing materials oriented strand board commonly referred to as osb is a type of engineered lumber similar to particle board formed by adding adhesives and then compressing layers of wood strands. And i am tired of taking chances. When they are used in roofing osb can retain heat and water perfectly. Table 2304 7 3 gives the 7 16 osb the ability to carry a roof live load of 40 psf pounds per square foot when spanning the same 24 inches.

For the roof we are hanging 2x6 in metal hangers and will screw the metal siding into them. Snap a vertical chalk line 1 4 inch from the rake edge of the roof using a chalk box. Osb is made out of strands of wood chips and chemically engineered materials to glue them together. Install the first metal panel on the low end of the roof square to the eave.

We are skipping the osb on the walls and the roof all together. As the result they are stronger and basically water proof. However the board is lack of natural moisture inside and won t dry as quickly as plywood. A potentially easier option is to use purlins on top of the rafters rather than framing between the rafters.

When the steel roofing can t carry the load other shear carrying materials such as 7 16 osb may be added to the assembly. I guess at 14x16 you won t be towing this one but the wind still blows and osb does not have adequate holding power to resist the wind trying to rip the metal roof sheeting off. In the case above the shear forces in the last 12 foot bay at each end of the roof have had osb placed between the roof purlins and the steel roofing. Begin on the left side of the roof working to the right.

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. Ensure that the line is square with the eave. Wind can get under these roofs. From the 2012 ibc international building code table 2304 6 1 over framing spaced 24 inches on center 7 16 osb fastened with 8d common nails six inches on center at the edges and in the field will support a maximum design wind speed vult of 110 mph miles per hour in exposure b or 90 mph in exposure c.

Unlike a house. Be sure the larger edge is laid so that the small edge of the next panel will overlap it.