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Minimum Thickness Most roofs will be sheathed in plywood at least 3/8 inch thick. That will suffice on a roof with rafters set 16 inches apart with minimal roof loads. Loads will vary with the pitch of the roof; the flatter the roof, the greater the load on any one section.
Can I use 1/2 inch plywood for shed roof?
If the shed is for light tools then 1/2 inch pressure treated plywood is acceptable. If the shed is for heavier storage, then pressure treated 3/4 inch exterior-grade CDX plywood is the best.
What kind of plywood is best for roofing?
Exterior Plywood is the preferred material for roofing. It also performs well when exposed to moisture over long periods of time. The price is low compared to other roofing materials and the installations are also easy.
What is the minimum thickness of roof sheathing?
Sheathing must be a minimum of 19/32-inch thick. Never affix roof sheathing with staples; 8d ring-shank nails need to be used instead. The normal thickness range for sheathing is 3/8 to 3/4 inch.
What grade of plywood is used for roof sheathing?
1/2 or 3/4-inch Plywood for Roof Sheathing? – Traditionally, 1/2-in CDX plywood was common choice with 24-in rafter spacing. However, heavier roof loads may require the use of 3/4-in CDX plywood for roof sheathing. Roofs with less pitch often carry heavier loads, including snow and ice accumulations in the winter.
What is better for roofing OSB or plywood?
Plywood Holds the Moisture Advantage Over OSB When plywood gets wet, it tends to swell. OSB takes longer than plywood to get saturated, but also takes much longer to dry out. When used as roof sheathing, this tendency to hold moisture means it will degrade faster than plywood when exposed to chronic leaks.
How thick should sheathing be?
The U.S. Department of Energy has determined that 7/16-inch sheathing is the minimum appropriate thickness for structural wall sheathing with an exception for gable end walls, where the minimum thickness is 3/8 inch.
Can you put new plywood over old on a roof?
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.
What thickness is 15 32 plywood?
1/2-inch NOMINAL VS. ACTUAL SIZES 1/4-inch 11/32 1/2-inch 15/32 5/8-inch 19/32 3/4-inch 23/32.
How thick should roof OSB be?
Standard roof sheathing thickness is ½” to ⅝” thick. If you are using OSB for your roof deck, then ⅝” is the recommended thickness. For plywood, which is slightly stronger than strand board, ½” thick is appropriate. Another factor is how far apart your trusses or rafters are spaced.
Should you use tongue and groove OSB for roof sheathing?
Tongue & Groove Boards T&G roof decking, however, looks classy and rich. In fact, T&G boards are most frequently used when the sheathing is visible from the inside such as in cathedral ceilings or in some cabin-style homes, especially if the span of the rafters is greater than 2 feet.
How many sheets of plywood do you need for a roof?
Divide the total roof area by 32 to get the number of sheets you will need to cover the roof. A typical 4 foot by 8 foot sheet of plywood covers 32 square feet. If your roof area is 1,600 square feet, 1,600 divided by 32 will mean you need about 50 sheets to cover the roof.
Is CDX plywood good for roof sheathing?
Moisture Differences In reality, CDX plywood can only withstand water for a short period of time. Do not use CDX for roofing, sheds, or other places that are exposed to moisture consistently. The sole exception to this is pressure treated CDX, which can survive for decades without even a protective coating.
What type of wood should be used for roofing?
Oriented strand board (OSB) – OSB is the most common type of material used for roof decking. It’s durable and readily available, and has relatively low costs. OSB is made of interwoven strands of wood bonded with adhesive.
Do you need H clips roof sheathing?
H-clips are referred to in the APA Guide as “edge support.” For the most common roof sheathing in our area, which is 1/2” nominal (7/16” actual) sheathing over trusses or rafters at 24” on center, there is no requirement for H-clips. One or two H-clips will often allow a longer span between roof trusses/rafters.
Which is cheaper plywood or OSB?
OSB is less expensive than plywood. To build a typical 2,400-square foot home, OSB may cost $700 less than plywood. OSB is considered by many to be a “green” building material because it can be made from smaller-diameter trees, such as poplars, that are often farmed.
Do I need plywood on my roof?
Aside from shingles and underlayment, plywood decking is one of the most important components in your roof. The plywood decking is integral in keeping your home free of unwanted water and mold. If the plywood has gotten wet, it can have a disastrous effect on the rest of your roof, especially the shingles.
How far should roof sheathing overhang fascia?
Ideally the sheathing should be on top of the fascia without extending beyond it. Guesswork can create a situation in which it extends too far and it interferes with flashing installation, or you have to cut it. If the fascia is to be one layer of 1x, I overhang the sheathing 5/8.
