Both oriented strand board (OSB) and plywood are substrate panels that can be cut and installed on a roof system. They share similar structural characteristics, are rated for the same exposure, have equal nail withdrawal resistance and share like installation methods. But while plywood led the market two decades ago, today, OSB is the most-used sheathing material on new roofs and re-roofs — and the more affordable option.

What Is OSB?

OSB is formed by adding adhesive to as many as 50 layers of wood strands and compressing them into the same thickness for consistent density. The overlap in plies prevents weak spots, giving OSB a greater load-bearing capacity than plywood.

The lack of internal gaps and voids also makes OSB water resistant.

Panels can be manufactured to specific thickness, strength, rigidity and size — up to 16 feet in length — whereas plywood is typically limited to 10 feet.

Atlas Installation Guidelines And Precautions

In 2019, Atlas approved the use of OSB sheathing as a suitable substrate for Atlas shingles.

And while OSB sheathing should not have any negative effects on shingle performance, contractors should get approval from their local building department, confirming that deck construction meets local code requirements.

Atlas Roofing’s installation instructions specify that manufacturing defects not related to roof decking should be settled in accordance with the terms detailed in the product’s Limited Shingle Warranty. In addition, Atlas provides no guarantees associated with this installation method and against any product deficiency, decking performance or shingle problems caused by the deck or substrate.

Important To Note

Although the use of OSB sheathing over deck boards has been approved, Atlas does not support this deviation of the decking requirement as a preferred method for installation of Atlas shingles.

For optimum performance, always follow the specific application instructions printed on bundle wrappers of Atlas shingle products.

For more information, visit AtlasRoofing.com.