Osb Under Flat Roof

Typical types of wood used for roof sheathing are oriented strand board known as osb and plywood the most popular being osb.

Osb under flat roof.

A homeowner recently wrote and asked me the following regarding osb roof decking. That s considered to be the minimum. This minimum wouldn t work if you have a flat roof. Most roofs are spaced at least 20 inches apart.

Adding osb is good when one is going to install insulation. Thicknesses range from 5 16 to 3 4 inch and the proper. A roof that lays practically flat will have a much heavier load than a steeper roof that allows rain snow and ice to roll right off. When you count sub floors roofs and wall sheathing osb claims about 70 of the wood sheathing market in north america over plywood.

If your roof is more on the flatter side then it s expected to have a heavier load. Osb comes in 4 by 8 foot sheets as does plywood but the manufacturing process allows the production of longer and wider ones. Mike the pole barn guru. Osb and plywood come in thicknesses ranging from 5 16 to 3 4 inch and the thickness needed for a particular roof depends on several factors including rafter spacing expected load and roof design.

This minimum will only work if the rafters are set 16 inches apart at most and if the roof doesn t have too much load. 5 thoughts on osb under steel roofing on pole buildings kamel may 3 2018 at 11 22 am. Then the top of all your purlins once osb under metal roof panels is placed will be in the same plane and the roof steel will lay flat. Odds are that if you pass a housing development of wood framed houses it will have osb oriented strand board as exterior sheathing.

Dear pole barn guru. 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. However you may need to consider bolstering the plywood thickness for a roof that has a higher load. Osb is widely used as roof decking material.

Rafters that are slightly farther apart might require inch or 5 8 inch thick plywood. With edge support and the same snow load 3 8 inch osb can be used. I found some pre made 4 inch pipe trusses.