How Thick Should Osb Be For Roofing

Standard roof sheathing which consists of 4 by 8 sheets of plywood or oriented strand board or osb is 1 2 inch thick and attaches directly to the roof rafters or the roof trusses.

How thick should osb be for roofing.

That will suffice on a roof with rafters set 16 inches apart with minimal roof loads. We re in dallas so we don t engineer for tremendous live loads for an asphalt shingle and we feel comfortable with 16 oc rafter spacing and 7 16 osb decking. Minimum thickness most roofs will be sheathed in plywood at least 3 8 inch thick. Thicknesses range from 5 16 to 3 4 inch and the proper one to use.

You need to find a sheathing with a span rating of at least 32 16 which means either 15 32 or 1 2 thick osb. With this thickness any deflection under dead loads only the weight of materials only should prove to be imperceptible. Osb is lightweight relatively inexpensive and strong enough to resist bending or breaking should someone walk on the roof. 8 tips for getting the best out of your oriented strand board osb how to install roof sheathing pro builder.

An exception to this standard however may occur if you intend to install slate concrete or tile shingles on your roof. For the curious 7 16 osb has a span rating of 24 16 and with supports every 24 inches is good for a roof live load of 40 psf pounds per square foot with a 10 psf dead load. With edge support and the same snow load 3 8 inch osb can be used. Plywood is a bit more expensive but is usually stronger and is often selected in cases where the roof covering is heavier such as for slate clay or concrete tile roofs.

Sheets of 7 16 inch thick with no edge support can be used in an area where the snow load is 30 pounds per square foot. Loads will vary with the. Osb comes in 4 by 8 foot sheets as does plywood but the manufacturing process allows the production of longer and wider ones. Roofing plywood sizes material wood joist and plywood or osb decking oriented strand board common 15 32 in roof decking material thickness osb or plywood for roofs walls roof deck materials to ensure a le.