For rafters spaced 20 or more inches apart, 1/2- or 5/8-inch plywood is recommended. The most common rafter spacing is 24 inches, and 5/8-inch plywood is recommended for that. It will support roof loads for most situations and is the standard for most roof applications.
What type of plywood should I use for a roof?
CDX is the grade of plywood most commonly used for roofing (CDX plywood means it is Construction Grade for exterior purposes). The wood is graded on each side from A to D, depending on the level of imperfections, (A being free of all imperfections and knots and D being un-sanded and considerably defected).
Which is better for roof sheathing 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.
What type of wood should I use 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 use treated plywood for roofs?
Contractors generally recommend treated plywood rather than regular plywood for roof decking because condensation can build up on the sheathing and cause rot. Roofers understand that when it comes to the roof deck, the amount of water that gets on the wood is a concern.
How much plywood do I 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.
How thick should flooring plywood be?
The recommended thickness of the plywood subfloor is governed by the spacing of the joists. Some experts suggest that 15/32-inch plywood should be standard if the underlying floor joists are spaced 16 inches apart or less, but slightly thicker 3/4-inch plywood should be used for joists spaced further apart.
Is 7/16 OSB OK for roofing?
…or a non-laminated panel, such as this OSB. Either one is acceptable. The typical thickness of roof sheathing is about 7/16-inch, which is just under 1/2-inch. … If you find 3/8-inch plywood installed as roof sheathing, it’s a good idea to make your client aware of its presence.
What is the best thickness for roof sheathing?
The recommended thickness for roof sheathing is ⅝” thick. Sheathing with a thickness of less than that is much more likely to result in bowing between framing which could potentially compromise your exterior roof material.
Why is OSB cheaper than plywood?
OSB can be manufactured into panels that are larger than plywood. OSB is more uniform, so there are fewer soft spots, such as those that can occur in plywood. OSB is less expensive than plywood. To build a typical 2,400-square foot home, OSB may cost $700 less than plywood.
What size wood do you use for rafters?
Max. Live Load 20 lbs/ft2 (956 N/m2)
|Maximum Span (ft – in)|
|Nominal Size (inches)||Rafter Spacing, Center to Center, OC (inches)||Lumber Grade|
|2 x 10||16||25′|
|24||20′ – 9”|
|2 x 12||12||33′ – 6”|
What kind of wood do you use for roof rafters?
Kiln-dried Douglas fir wood presents the number one choice for building a rafter-styled roof in a wood frame house.
Do I need treated timber for roof?
The simple truth is that you do NOT need to treat timber. … The same goes for actual rot by fungus – timber is simply NOT going to rot if it is kept dry.
How much does it cost to replace plywood on a roof?
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. A 4 x 8 sheet of plywood covers about 32 square feet of roof area—and the average roof measures about 3,000 square feet.
Do I need pressure treated plywood for shed roof?
Ordinary exterior-grade plywood is made with weather-resistant glue, but the wood itself is not particularly rot resistant. This is why pressure-treated plywood is best for a shed floor. Even a floor that’s raised off the ground a bit will last longer if it’s made with pressure-treated plywood.
Can you use treated plywood on a deck?
Short answer, no… Long answer, you can but even if you use exterior rated plywood, you will still have sever warping and strength and rotting issues.