Is it OK to use OSB for roofing?

Both OSB and plywood panels can cut and installed on a roof using conventional roofing equipment. They have similar structural characteristics, and can be used interchangeably.

What thickness OSB should be used for roofing?

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.

What is the best material for roof sheathing?

1) Plywood

This sheathing option is considered one of the strongest and more durable options. Typically, they come in 4-foot by 8-foot sheets. Rafters and joints that are spaced further apart will require thicker sheets of plywood to prevent roof sagging.

Can you use OSB roof sheeting?

You can use an OSB body for the exterior roof sheathing on your home. The OSB material is different from plywood. But it has become increasingly popular for roofers. It's all thanks to how well the OSB material can stay strong and secure for long-term use.

Can I use OSB board for flat roof?

The material used for the roof deck must be moisture resistant and will usually be plywood, OSB or timber boards although concrete and woodwool slab or profiled metal can also be used. Ordinary chipboard is not recommended as it may absorb moisture when damp and lose its structural integrity.

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Can 7/16 OSB be used for roof sheathing?

...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.

Can OSB roof sheathing get wet?

Your framing lumber and the oriented strand board (OSB) are going to be fine. The glues used to make OSB are water-resistant because the manufacturers know that virtually no one can build a home that won't get wet before the roof and siding is applied.

What wood is best for roofing?

Cedar has earned a reputation for being strong, flexible, and weather resistant – qualities that make for an effective roofing shingle. Among roofing shingle manufacturers, cedar is the go-to material, all thanks to its durability.

Can OSB be used outside?

OSB can be used for outside applications. However, those OSB boards are classified as class 3 and they are appropriate for use in humid conditions. Even if you buy OSB that is waterproof from the market, you should apply an additional layer of waterproofing for protecting the board from moisture or water.

Does OSB board warp?

OSB is built by pressing smallers strands of wood together with glue and wax in a hot press. OSB looks a lot like a collage of different wood chips. Unlike it's plywood counterpart, OSB lacks the forces that tend the wood to warp, and so is easier to get perfect dimensions and avoid warping tendencies.

Is OSB board water resistant?

As a general rule, most OSB are water resistant. Due to their construction process using wood strands, resins and wax they come fairly water resistant. However, if you're looking for a truly waterproof OSB you need to make sure it is stamped stating so.

Can 3/8 OSB be used for roofing?

With edge support and the same snow load, 3/8-inch OSB can be used. Edge support is typically provided by tongue-and-groove sheathing panels or panel clips. A 4-by-8-foot sheet of OSB or plywood is 32 square feet. To determine the quantity needed, use your roof's total square footage and divide by 32.

Can you use 1/2 inch plywood for a roof?

Most Common Thickness

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 sheeting is used for roofing?

Usually, roof sheathing is made of wood. It can come in the form of plywood or oriented strand board (OSB). OSB is less expensive, but lighter and far more fragile, which is why many roofers rely on plywood.

Which side of OSB should face out?

Using OSB Safely

When installing in vertical applications such as wall sheathing, you'll want to orient the smooth or stamped side facing out. The smooth side has a better moisture resistance and will ultimately provide better performance against weather.

Can you use screws on OSB?

There are many types of screws for plywood and OSB subfloor. You'll want to use #8 1-1/2 inch wood screws spaced 8 inches apart to secure a 5/8″ OSB subfloor to the floor joist or floor truss. For 3/4 inch plywood, it would be best to step up to a 2-inch wood screw to account for the added thickness.

Can I use screws for roof sheathing?

Screws can be used for even greater withdrawal strength, but should be sized by the building designer. Staples are not recommended for roof sheathing attachment in high-wind areas. It is extremely important to have proper fastener spacing on all panels.

What happens if it rains on OSB?

Our OSB is rated “Exposure 1” and that means that it will withstand normal delays in construction. Normal delays and the rain you indicated will not affect the structural properties of the panels. Certainly it would have been better to have covered the roof with a tarp or roofing felt before it rained.

How long does it take OSB to rot?

Sheets situated so they air dry on both faces between wettings will outlast those that only dry on one side or are always damp. OSB, which is unable to dry out, can rot within a matter of months, while panels that can dry out may last more than a decade.

How long does OSB last in rain?

OSB 3 is classified as resistant to humid conditions. This is a liability choice to avoid misunderstandings. We have had OSB 3, also in horizontal orientation, exposed to rain for at least 4 months.

What thickness of plywood is used for roof sheathing?

What Size Plywood for Roofing. 5/8-inch plywood is the most common choice for roofing with 24-inch rafter spacing. It's also the standard for most roof applications because it supports roof loads in most situations. However, heavier roof loads may require 3/4-in CDX plywood for roof sheathing.

How Far Can 3/4 OSB span?

h. Maximum span 24 inches where 3/4-inch wood finish flooring is installed at right angles to joists. i. Maximum span 24 inches where 1.5 inches of lightweight concrete or approved cellular concrete is placed over the subfloor.