OSB roofing is widely used in both commercial and residential construction. Sometimes, construction works can get paused for bad weather like rain showering. So, it’s normal to become tense at that time thinking can OSB roofing get wet? Well, it’s okay to be worried.

And, yes, OSB roofing gets wet but it takes time to get wet. Wisely saying, OSB roofing is water-resistant. However, the difficulty with OSB roofing is that every cut is vulnerable to water and expands when wet.

To know in detail, read the article till the end.

Can OSB Roofing Get Wet?

When OSB roofing becomes wet, it swells around the edges, which remain enlarged even after it has dried. Though OSB roofing is water-resistant, it’s not okay to put it in a rain shower. So, be extra careful with your OSB roofing. 

Problems You Can Face When OSB Roofing Get Wet

Water won’t totally destroy OSB. But, you can face some problems when your OSB  roofing gets wet. Here, we explain it for your needs.

  • As water is absorbed and released, it will expand and shrink. And, it’s a problem for the house.
  • Moisture build-up in the OSB roofing may lead to fungus and wood decay.
Can OSB Roofing Get Wet

How You Can Protect OSB Roofing from getting Wet

You can apply waterproofing and protect your OSB roofing from getting wet. To apply waterproofing, you need to follow some steps. 

Step 1:

When purchasing OSB, make sure it is branded with the word “waterproofed”. To some extent, every OSB is designed to be water-resistant, but every amount boosts your final result.

Step 2:

Cut your OSB into the sections you’ll need before applying your waterproofing to protect the margins. All of the parts must be measured, marked, and cut, then placed in the tarp. Also, ensure that there is no dust or grass in the OSB roofing.

Step 3:

A quality outer paint may improve the water resistance of your OSB while also adding color to your project. If you plan to color your OSB roofing, use this before the waterproofing.

Both oil-based and latex-based coating can work in this situation, but make sure you choose a high-quality type.

  • First of all, sand the surface of the roofing lightly. It is to roughen up the existing sealer so that the paint adheres better.
  • Then, paint the surface of the pieces using a paintbrush.
  • Let every piece dry perfectly and then flip or apply more coating.

Step 4:

Brush the surface and ends of the OSB pieces with the sealer. Assure that you do this on all sides, not just the one where you made your cuts.

Allow 12 to 14 hours for the waterproofing to dry while they lay on the tarp. To guarantee that the wood is fully protected, you can apply more layers of waterproofing. Your dry periods may be extended in a humid area.


Well, hopefully, you’ve got the answer to can OSB roofing get wet. So, handle your OSB roofing with extra care.

Have a sunny day. All the best.


As a civil engineer and roofer, I love to share the experience that I have gained through the last couple of years. In the roofing industry, practical experience is a very crucial fact that can help you a lot. Hence, I want to help you with my blog.

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