4 Factors On How Long To Dry OSB Board In Water Damaged Wall

If you use them as wall sheathings, you must know how long to dry OSB board in water damaged wall. If you let them stay wet for too long, this can facilitate the process of rotting and mold build-up, which are the last things you’ll want inside your home.

Oriented Strand Board (OSB) can be used in various structures such as flooring, wall sheathing, roof cover, and even furniture. However, like wood, this material is still susceptible to rot even if they are made to be water-resistant. To help you get past this situation, we provided several ways that you can do for your OSB boards.

how long to dry osb board in water damaged wall


What Happens When An OSB Board Get Soaked

These engineered wood boards are primarily created to withstand water which is always present in every home. Even so, they are still not recommended to be exposed to excessive moisture.

OSB tends to degrade quicker than other wood materials when they become wet and dry repeatedly. Other than that, these are the things that could also happen if were left unprotected from water damage:


Fungal growth

Moist OSB can foster fungal growth because they already have mold spores in them. Minimal contact with moisture can still trigger mold that starts from within.

It is necessary to get rid of them as early as possible because they spread quickly. Molds are also toxic and can harm you and your family members with respiratory problems.

Fortunately, they can be removed using a mixture of ordinary detergents and water. You can also use bleach to sanitize the area and prevent them from coming back in the future.



OSB absorbs water at a slow pace, but when they do, drying can take time before all of the moisture is removed. The slow progress can make the insides of the sheathing rot, eventually affecting nearby boards.



Swelling happens when the boards absorb too much moisture either from water contact or from the air. Although they do not cause leaks, they can trigger fungal growth and rot.

You can still fix it by sanding the edges and the thickened area. The swelling can also go away if the board is completely dried out.


How Much Moisture Does An OSB Tolerate 

When thinking about this material, it’s important to note that OSB is water-resistant but not waterproof. The way these boards are specifically manufactured is to have minimal gaps between strands. They are filled with resin adhesive and wax to make them more solid and sealed.

However, when the boards are cut into pieces, the edges serve as an opening for moisture. Excessive dampness causes several results that can permanently damage your boards.

Different types of OSB have a preference in terms of atmospheric conditions, and it will determine the life of your sheathing boards. These are the four grades that you should know about:



OSB/1 is generally used as interior panels and furniture material. It works well in dry conditions.



OSB/2 are stronger panels that are mostly used for load bearing. Similar to the first grade, they are best to use in dry areas.



This can also be used in load bearing, but they are made to be water-resistant, so they work fine in humid conditions.



This grade is heavy-duty and works fine in either dry or humid conditions.

Leaving the OSB alone would make it more vulnerable to water damage. You can use paint, layers, stain, or treatments to extend its lifespan. If used outside and often exposed to rain, they will eventually dry out as long as they are covered with a topcoat.


How Long Does It Take For An OSB To Dry

Depending on the amount of water that penetrated the panels, the number of days it can take for an OSB to dry varies. When the OSB is exposed to natural elements such as rain and humidity without treatment and protection, the possibility of it degrading over time is high.

Soaked panels can take for up to 8 weeks to dry without the help of any equipment. If they take more time than that, the swelling can get severe and might trigger irreversible problems. You can also leave them to dry naturally as long as there is proper air flow.

Luckily, there are some things that you can do to prevent this from happening:


1. Dry them as early as possible

If you are aware that the OSBs in your home are exposed to water, be sure to dry them out quickly. Don’t allow the water to have time to penetrate the boards because even a tiny amount of moisture can do significant changes to the panels. Wipe the excess water on the surface.


2. Use carpet drying fans and a dehumidifier

Carpet drying fans can accelerate the drying process. Essentially, this will promote an airflow that will help the moisture from the wood evaporate faster.

If it’s inside, open the windows and doors for better air circulation. You can also use a dehumidifier to exhaust dry air into the affected OBS.


3. Pay better attention to the cuts and edges

Edges and cuts are more exposed, and this is where the water usually creeps in. When drying the boards, focus the pressure more on the edges to secure that you also reach the insides.


4. Test the panels with a moisture meter

Moisture meters can help determine the moisture in the OBS. You can use this to see how much longer it needs to dry the boards. You can also determine if the OBS can still be saved or needs complete replacement.



There’s no one way to know how long to dry OSB board in water damaged wall because every situation varies. Depending on the level of the panels’ dampness, it can range from hours to days and even weeks. It would be best to use a drying tool so it would be faster and more efficient.

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