What size roof sheathing should I use?

Roof sheathing comes in grid-marked 4-by-8-foot sheets, and should be installed perpendicular to the frame. Sheathing should be a minimum of 19/32-inch thick. Never attach roof sheathing with staples; 8d ring-shank nails should be used instead. The typical thickness range for sheathing is 3/8 to 3/4 inch.

What size plywood should be used for roofing?

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. Roofs with very heavy loads may require 3/4-inch thickness.

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.

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What type of sheathing 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 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.

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.

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. … Oriented strand board (OSB) is one of the most popular materials for roof sheathing.

When placing underlayment over sheathing for roofs with a slope of 4 or less the commonly used roofers felt is?

Underlayment On Standard Slopes where Asphalt Roof Shingles are Installed. As stated in Best Practices Guide to Residential Construction: On roofs with a slope of 4:12 or greater, use a single layer of 15 lb. asphalt-saturated felt, starting at the eaves and lapping upper courses over lower by a minimum of 2 inches.

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Is OSB stronger than plywood?

Wood fiber is used more efficiently in osb. Osb is stronger than plywood in shear. Shear values, through its thickness, are about 2 times greater than plywood.

Is OSB good for roof sheathing?

Suitability for Roof Sheathing

Both the National Roofing Contractors Association and the Asphalt Roofing Manufacturers Association recommend the use of OSB for roof sheathing, as long as it bears the approval stamp of the APA – Engineered Wood Association.

Can plywood roof sheathing wet?

A: It is never a good idea to install a roof over wet plywood or any type of roof sheathing. Trapped water will boil when the sun heats the roof and the shingles will then have small pits where the steam finally escapes.

Should plywood go under metal roof?

For many applications, a layer of plywood underneath your metal roofing is an unnecessary expense. … Boards measuring 1 inches by 4 inches or 2 inches by 4 inches are commonly used for purlins, though never use treated lumber because it will corrode the steel roof and fasteners.

How do you install roof sheathing yourself?

  1. Step 1: Check That Rafter Ends Are Level for Nailing Surface. You want to be sure that the rafter ends form a straight line. …
  2. Step 2: Ventilate the Roof. …
  3. Step 3: Apply the Roof Sheathing Panels. …
  4. Step 4: Cover the Roof Sheathing with Shingle Underlayment Felt. …
  5. Step 5: Install the Roof Shingles.

What type of plywood is used for roof sheathing?

CDX Plywood

A special grade of plywood called “CDX” is a popular choice for roof sheathing.

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How thick should exterior plywood sheathing be?

The International Residential Code specifies 3/8-inch plywood for sheathing walls with a standard stud spacing of 16 inches, if the siding is nailed to the studs through the sheathing. If the nails penetrate the sheathing, but not the studs, the minimum plywood thickness that the IRC designates is 1/2 inch.

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.

Roofs and roofing