The recommended maximum gap between roof sheathing boards for low-quality, 3-tab shingles is 1/4-inch. If asphalt shingles are installed over sheathing with gaps exceeding 1/4-inch, over time, these gaps may telegraph through and become visible.
How much space do you need between roof sheathing?
APA recommends a 1/8-inch space between panel edge and end joints. Plywood and oriented strand board (OSB), like all wood products, will expand or shrink slightly with changes in moisture content. If the wood structural panels are tightly butted, there is no room for expansion and buckling can occur.
How do I know if my roof sheathing is bad?
Other signs of this will be ceiling and wall spots, the material beginning to buckle and fall away, and similar issues. As it worsens, you may also see sagging rooflines and buckles or other deformations visible underneath the shingles or other materials, as well.
Does OSB board expand?
Expansion gaps allow the boards to expand unrestricted before reaching the equilibrium moisture, which is likely to happen if the panels are not conditioned to the end-use climate before being installed.
Should there be a gap between roof and wall?
All spaces between your roof and walls must be properly sealed. … Your roof overhang should extend at least 3/4 to 1 inch beyond your roof to keep water from running inside your walls. Downspouts that are clogged are also a common cause of water leaking into small gaps.
What is the minimum thickness of roof sheathing?
Roof Sheathing Code Requirements
The minimum requirement for roof sheathing is ⅜” thick. There is no upper limit on how thick your roof substrate is. Thickness allowed depends on how far apart rafters or trusses are spaced and the rating of your roof decking.
Can you put new roof sheathing over old?
The new plywood will have to be nailed to the rafters or roof trusses. … But, with the old plywood left in place, it will be considerably more difficult to locate the rafters to ensure proper nail placement.
How much does it cost to replace roof sheathing?
The thicker the plywood your roofer uses, the more expensive the job will be. Your price could vary depending on how much the roofing company charges for labor, but generally you can expect to spend between $70 to $100 for each sheet of plywood.
Can rain get in roof vents?
And on occasion a hard driving rain with whipping wind will cause roof vents to leak water. If your roof vent leaks during heavy rain, the rain may be blowing up under the hood and into the vent. It this is the case, you need to create a breathable shield to slow the driving rain drops while still allowing air flow.
What is considered spaced decking?
The deck must provide a smooth and sound substrate. … There should be no gaps or spaces between the deck boards greater than 1/4” (6 mm). If there are gaps or spaces between the deck boards greater than 1/4” (6 mm), an approved deck must be installed over the deck boards.
What size nails should I use for roof sheathing?
Step 3: Fasten Roof Sheathing Panels Properly. Fasten panels with a minimum of 8d Common (0.131-inch by 2-1/2-inch) nails spaced a maximum of 6 inches on center at supported panel ends and edges. At intermediate supports, fasten panels 12 inches on center. In high-wind areas, more fasteners may be required.
What is considered solid sheathing?
What is a solidly sheathed deck? A solidly sheathed deck means the roof has a solid wood surface to which asphalt (and other types of roofing materials) shingles can be fastened. This is code but also just good practice.
Does OSB expand more than plywood?
Osb is engineered to have strength and stiffness equivalent to plywood. … When osb is exposed to wet conditions, it expands faster around the perimeter of the panel than it does in the middle. Swollen edges of osb panels can telegraph through thin coverings like asphalt roof shingles.
Can you use screws on OSB?
Screws – and DO NOT use drywall screws. Use coarse thread coated deck screws 1 5/8″. OSB will pop the head off a drywall screw, even with a drywall screw bit on the drill. And the fine thread on a drywall screw will not hold in a joist – it will spin and strip the threads when the head hits the OSB.