Osb Vs Plywood For Shed Roof

Oriented strand board isn t plywood nor is it a type of particleboard fiberboard or wafer board and although it is a newcomer to a plywood dominated market its use for exterior sheathing is.

Osb vs plywood for shed roof.

In 2001 oriented strand board surpassed plywood in terms of square footage produced. Osb is now used for about 70 percent of all floor wall and roof sheathing in north america. 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. However you might find that osb can better suit your needs than plywood for the roof.

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. This can result in visible deflection of the panels between the supports and can telegraph through causing a wavy appearance to the roof. New homes will usually see a few rainfalls before a roof is on and as noted above osb doesn t handle moisture well. 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.

The lower the slope the more weight for snow load but less wind force. Because of its construction some manufacturers actually make larger sheets of osb. University of massachusetts meets most building codes for roof and wall sheathing. 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. Osb boasts a more consistent density. Compared to cdx oriented strand board osb is made very differently.

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. The higher the slope the more quickly the snow and rain will be shed but also the greater the wind force. Plywood is better than osb for subfloors. Despite its common use as such we don t recommend using osb for subfloors but that s really just for aesthetic reasons.