5 Facts You Didn't Know About Roof Sheathing


Roof sheathingWe spend a lot of time talking about shingles on our blog, but we rarely mention the essential foundation of shingles – sheathing! Your roof’s sheathing is that layer of wood between the rafters and the shingles. It serves as the flatbed for roofers to nail shingles into.


Here are 5 valuable pieces of information about sheathing that you probably didn't know.


Sheathing isn’t always called sheathing

If you see the term “decking” or “wood decking” in reference to a roof, it’s the same thing as sheathing. Depending on which roofer you talk to, they’ll use different terms to refer to the same part of your roof.


There are different types of roof sheathing

While roof sheathing is typically made out of wood, there are different types of wood that can be used to install this portion of a roof. One type is oriented strand board, or OSB. Because it’s lightweight, affordable, and durable, OSB is many roofing contractors’ first choice when it comes to sheathing. The durability of this wood allows roofers to walk on it without breaking or even bending it.


The other material commonly used for sheathing is plywood. You’ll pay a little more for plywood than you would for OSB, but the advantage of plywood is that it’s stronger. If your roofer recommends plywood over OSB, it’s probably because you’ve chosen heavy tiles to cover your roof such as slate or concrete.


Your roof’s slope determines the thickness of your sheathing

The steeper the slope of your roof, the thinner the sheathing will be. That’s because a steep roof won’t allow snow or water to sit on it and therefore does not need the added support of thicker sheathing. Flatter roofs, however, need strong sheathing to support the weight of standing water or piled snow.


Regardless of the grade of your roof, though, your sheathing must be thick enough to:

  • support a roofer walking on it during the installation process as well as during roof inspections.
  • comply with your neighborhood and/or city housing regulations.

Sheathing in poor condition could annul a warranty

Never ever put new shingles over damaged sheathing. Doing so may cover up your roof’s problems, but it will also multiply them. For example, a roof with damaged sheathing won’t hold up for the life of your shingles; however, your shingles' warranty will likely be invalid if you’re guilty of not replacing the sheathing when you re-shingled last time.


In the end, the shortcut that saved you money initially (keeping old sheathing) will end up costing your more money because you’ll have to replace your roof sooner than you otherwise would have. Not to mention, faulty sheathing causes a lot of internal damage to your home if you end up with a leak or soft spot in the roof.


Sheathing needs a barrier

While your shingles mostly protect your sheathing from the elements, you also need a moisture barrier known as underlayment. There are different types of underlayment (asphalt-saturated felt, synthetic underlayment, rubberized asphalt underlayment), but they all protect your roof during the installation process and throughout its lifespan – especially in inclement weather that may cause you to lose a shingle or two.


You have options

Sheathing is a non-negotiable. It's a necessary part of your roof that also comes with a price tag. However, Joye Roofing in Columbia, SC makes the price point for roof replacements much more realistic by offering financing options. Give us a call at (803) 219-8157, or click on the banner below to learn more about our roof financing opportunities.


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Derek Joye has been roofing homes and businesses in the Midlands for over 10 years.