Several factors must be considered when determining appropriate roof sheathing thickness such as the.
Roof sheathing material thickness.
Comes in standard 4 by 8 foot sheets is strong durable and relatively light.
If you re in search of quotes for a roof sheathing job improvenet can put you in touch with up to four local contractors for free.
Required sheathing thickness for roofing important factors.
I ve never used commodity osb on a roof but it s probably fine in 5 8 thickness and possibly in 1 2 thickness.
I just read somewhere actually in taunton press roofing with asphalt shingles book that one should consider using sheathing thicker than code to avoid sagging between rafters.
Roof sheathing materials plywood.
Typical types of wood used for roof sheathing are oriented strand board known as osb and plywood.
And for wood structural panel sheathing r803 2 2 allowable spans.
Loads will vary with the.
Sheathing comes in different thicknesses and what type of roof you have will help designate what type of thickness you need.
It also holds roofing nails well.
The roof covering will be asphalt shingles.
And if you re still wondering what roof sheathing is and what materials are typically used read on and satisfy your curiosity.
The common grade of plywood for roof sheathing is cdx.
That will suffice on a roof with rafters set 16 inches apart with minimal roof loads.
It spans the rafters to support the roofing and in the case of panel sheathing such as plywood or osb it acts as a diaphragm with the walls to resist horizontal loads.
As per code in my area ottawa canada i plan on using 3 8 plywood for sheathing.
Unlike with plywood siding the plywood sheet to be used for sheathing should be at least 3 8 inch thick.
Cdx works fine in 1 2 or 5 8 thickness.
Malcolm i almost always use 5 8 zip sheathing on roofs and metal roofing installers have never questioned it.
You would go to table r503 2 1 1 1 to determine minimum nominal panel thickness.
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.
That s considered to be the minimum.
Minimum thickness most roofs will be sheathed in plywood at least 3 8 inch thick.
Many code requirements are not inspected.
According to 2009 irc table r803 1 minimum thickness of lumber roof sheathing.
For information on large panelized roof systems refer to the commercial construction application section.
Steeper roofs tend to have thinner sheathing due to not much weight being applied to the roof while flat and low sloop roofs that are likely to gather weight from precipitation or people walking on it.