Osb Vs Plywood For Shed Roof

Osb is made by combining glue resin and wood chips and pressing them into the shape of a plywood sheet then baking everything together.

Osb vs plywood for shed roof.

Today you can find osb in thickness from 7 16 to 1 1 8 for different applications from roof wall subfloor i joists and everything between. Even though plywood is more expensive and osb stronger my recommendation for a shed roof is 5 8 or 3 4 construction grade exterior rated cdx t g plywood. Plywood is better than osb for subfloors. Both cdx plywood and osb tend to come in standard sheets of four foot by eight foot 4 8.

While a sheet of plywood might be 5 to 7 plies thick a sheet of osb is made from as many as 50 strand layers packed and compressed into the same thickness. 2x greater shear strength than similar sized plywood source. However you might find that osb can better suit your needs than plywood for the roof. The higher the slope the more quickly the snow and rain will be shed but also the greater the wind force.

Because of its construction some manufacturers actually make larger sheets of osb. Despite its common use as such we don t recommend using osb for subfloors but that s really just for aesthetic reasons. The lower the slope the more weight for snow load but less wind force. Osb boasts a more consistent density.

Building codes the engineered wood association architects and most builders rate plywood and oriented strand board obs sheathing equal in strength and durability. New homes will usually see a few rainfalls before a roof is on and as noted above osb doesn t handle moisture well. Because of this manufacturing process osb is at least half the cost of cdx plywood. Osb panels can be manufactured in lengths up to 16 feet or sometimes even higher while plywood is generally limited to 8 to 10 feet.

Compared to cdx oriented strand board osb is made very differently. This can result in visible deflection of the panels between the supports and can telegraph through causing a wavy appearance to the roof. University of massachusetts meets most building codes for roof and wall sheathing. Secondly osb panels have a higher shear rating than plywood panels and are thus often installed with greater spans than plywood of the same thickness.