How Thick Should Osb Be For Roofing

Osb roof decking thickness 7 16 1 2 or 5 8.

How thick should osb be for roofing.

Thicknesses range from 5 16 to 3 4 inch and the proper one to use. With this thickness any deflection under dead loads only the weight of materials only should prove to be imperceptible. 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. That will suffice on a roof with rafters set 16 inches apart with minimal roof loads.

An exception to this standard however may occur if you intend to install slate concrete or tile shingles on your roof. 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. Minimum thickness most roofs will be sheathed in plywood at least 3 8 inch thick. Loads will vary with the.

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. Osb is lightweight relatively inexpensive and strong enough to resist bending or breaking should someone walk on the roof. 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 edge support and the same snow load 3 8 inch osb can be used.

Typical types of wood used for roof sheathing are oriented strand board known as osb and plywood the most popular being osb. 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. Osb comes in 4 by 8 foot sheets as does plywood but the manufacturing process allows the production of longer and wider ones. 8 tips for getting the best out of your oriented strand board osb how to install roof sheathing pro builder.