The regular homeowner might not think much about how their roof works or any of its components, such as their roof decking. However, the secret material that helps to hold everything together is the plywoods that are installed underneath the roofing shingles. Plywood or roof sheathing as it is sometimes called, is the main layer underneath the shingles and underlayment papers. The sheathing also connects the frame of the house to the roof itself and provides an extra layer of protection in keeping your roof safe.

While there are multiple benefits of having a plywood decking, the main drawback is that, since the sheathing is hidden and not visible, damage can start brewing and not be noticeable until its too late.

In this article, we highlight 6 things to know about your roof decking. From what makes a roof decking to how much it costs to re-deck your whole roof.


roof decking inspection

1. Roof Decking: What Is Its Purpose?

Many homeowners might not think about their roof until there are issues or even think about their roofs at all. The main function of the roof decking is support. Asphalt shingles are heavier than you might think, each shingle weighs approximately 2.5 pounds. The shingles, plus all other components that go underneath, such as the underlayment and ice and water shield papers add even more weight for the ply-woods to support. Therefore, its essential for the decking to be in pristine condition.

2. Types of Roof Decking

  • OSB or Oriented Strand Board Sheathing – Oriented Strand Board or OSB is crucial for roofing contractors, as it is the most common type of roof decking in today’s roofing industry. OSB roof decking is durable, less expensive than other materials and there is always a wide selection to choose from. This sheathing is manufactured from softwoods, these are then chipped into thinner strands that are compressed together, creating a more durable board. The strands are thrown in a mixture with glue and treated with wax and resin, then heated with high pressure in order to melt the wax and resin to bond the strands together.
  • Plywood – Plywood is made from plies of wood glued together, pressed and then heated together. These plies of wood are glued together, with each layer laying crosswise beneath it. Giving these plywoods greater structural force and compacting it into stronger ply-woods.
  • Plank Sheathing- Normally used on wood shakes, these are spaced about one and a half inch from each other.

3. How To Know Your Roof Decking is Damaged or Needs to be Changed?

If you notice a leak coming in through your ceiling, then its most likely that rain water is coming in from your shingles or perhaps, your chimney flashing. When damage has been present for a while and left untreated, it will most likely penetrate all the way through to the roof decking. In order to repair your roof deck, you need to contact a roofing contractor to make an inspection first. This way, they will be able to determine the source of the leak and let you know what can be done to repair it. The process usually consists of removing some shingles along the area, as well as replacing any underlayments or ply-woods that have damage and installing brand new ones instead.


roof decking damage plywood is being changed


4. How Do You Know Its Time to Replace Your Entire Roof Deck?

This question is similar to the one above, the first thing to do is to contact your roofing contractor and have them inspect your roof. They will be able to tell you which plywoods need to be replaced and which ones are in good shape. Some signs that your plywood is damaged is leaks, wavy or uneven ceilings, or sagging parts of your roof(that you can see from the outside). However, it can be difficult to tell, so we always suggest to call a roofer first.

5. Can a Homeowner Make Their Own Decking?

Certainly! Building your own decking can be done by a single person if you have a smaller roof and the necessary expertise, of course. However, if its a big or even a really steep roof, then its best to call your local roofer. They will be able to handle a proper roof decking installation in no time and be done in a day or two. This way, you wont be letting your open roof be exposed to possible rain and will have a solid foundation for the rest of your roof.

6. How Much Does a Roof Decking Cost?

Roof decking costs depend on each house and how much work is being done. If the job only includes replacing a couple of plywoods, then it won’t cost as much as if you were having your whole roof deck replaced. For a whole new deck, the price depends on different terms. Such as the size of your roof, the type of decking materials you want to use and labor costs. In order to get a good average cost, contact a couple of roofing contractors and ask them to provide their expertise and quotes for the project.


The professionals at Oscar Roofing are able to provide their expertise and insight for your next roofing project. When looking into roof repairs or simply wanting to re-deck your roof, contact us for a free inspection. We are able to answer all your questions and provide plenty of information in order for you to make your best decision when it comes to your home.