Lay sheets in rows with the long edge horizontal to the roof bottom.
Roof osb sheathing 24 truss spacing.
For rafters spaced 20 or more inches apart 1 2 or 5 8 inch plywood is recommended.
A structure s roof truss spacing can vary from every 12 to 24 inches.
I would first verify what you actually have by looking for a stamp on the roof sheathing.
Apa e30 01 american plywood association engineered wood construction guide e 30 indicates that 7 16 osb for roof sheathing with supports 24 o c.
With edge support and the same snow load 3 8 inch osb can be used.
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.
That can mean costly time consuming callbacks.
Roof sheathing panel spacing hints.
If the roof live load exceeds 40 psf alternate roof sheathing must be utilized.
Typical types of wood used for roof sheathing are oriented strand board known as osb and plywood the most popular being osb.
If the wood structural panels are tightly butted there is no room for expansion and buckling can occur.
Boards require a minimum of two nails per truss while sheathing requires six nails due to face width and nail spacing.
May only be used where the roof live load design snow load is 40 psf or less.
Apa recommends a 1 8 inch space between panel edge and end joints.
1 2 inch osb or plywood roof sheathing is often sold with other thicknesses such as 7 16 inch or 15 32 inch.
These little changes can effect the maximum spans allowed by code and you can find the label stamped on the sheathing.
Use a 10d box 0 128 inch by 3 inch nail as a spacer to gauge 1 8 inch edge and end spacing between panels.
Spacer type panel edge clips are available from some manufacturers.
The minimum osb panel size is 24 inches in any direction and each sheet end must rest on a rafter.
Plywood and oriented strand board osb like all wood products will expand or shrink slightly with changes in moisture content.
The most common rafter spacing is 24 inches and 5 8 inch plywood is recommended for that.