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Can You Put Drywall Mud Over OSB? (How To)

You have an unfinished room in our house but you don’t want the hassle and expense of hanging and sanding drywall. Do you find yourself wondering if you can put drywall mud over OSB?

You can put drywall mud over OSB if the OSB has not been exposed to water and is not damp. The water content in drywall mud will not harm the OSB. Applying several thick coats of drywall mud will seal and harden the board.

putting mud on the drywall

OSB, or oriented strand board, is made of strands of wood that are held together by an adhesive and resin coating. The wood strands are placed in alternating layers, running parallel to each other. Each board, on average, is at least 50 strands thick, making OSB stronger than plywood.

When we think of OSB, we often think of something that is unfinished. We see OSB when a house is in the process of being built or when a roof is being repaired. But OSB is now being used for so much more.

Many homeowners find applying drywall mud to OSB instead of hanging drywall to be a much more simple process. There is minimal to no sanding and the price is more affordable. OSB is much more cost-effective than sheets of sheetrock.

Whether you are wanting to create a Mediterranean look, give your home a warm and rustic look, or you have a rental that you want to ensure can withstand a variety of renters, using drywall mud over OSB is an affordable way to achieve what you are after.

Should You Put Drywall Mud Over OSB?

putting mud on the drywall

You love knowing that OSB gives your walls more strength than drywall and you love the creative ways to use OSB. But should you put drywall mud over OSB?

You should not put drywall mud over OSB if you do not have the time or patience. Depending on the final look you are going for, several coats of drywall mud may be required. Each coat must thoroughly dry before applying the next one.

OSB is already a water-resistant material so the addition of a water-based drywall mud will not harm the wood board but care needs to be taken when mixing the mud. You do not want the mud too watery because that will prolong the drying time between coats and will also cause the OSB to swell.

Coating OSB with drywall mud also requires a lot of patience. At least 24 hours of dry time is required between each coat of mud. And, depending on the final look you are going for, there may be multiple touch-ups with the drywall mud, filling in any holes or cracks.

What Tools Do You Need To Put Drywall Mud Over OSB

tools for drywall

Before you begin your new project, it is important to take the time to get all your tools ready beforehand. So what tools do you need to put drywall mud over OSB?

The tools you will need to put drywall mud over OSB are easy to find at any hardware store. You will need sheetrock mud, a concrete binding agent, a trowel and joint knife, a paint brush roller, and a flexible hold joint tape.

When gathering your list of tools, it is also important to include any personal protective equipment. You will not have the dust hazard normally associated with drywall mud but there is still a risk to your eyes, lungs, and skin.

Wearing thick rubber gloves will protect your skin when mixing the drywall mud. Safety glasses are also recommended. Whether you are adding a concrete bonding agent or simply mixing the mud, the gloves will protect your skin from any splashes.

Another vital piece of personal protective equipment is an N95 dust mask. Drywall compound is an extremely fine powder that can easily be inhaled. The chemicals can be extremely dangerous to the lining of your nose and lungs.

Wear a tight-fitting mask that provides a snug fit around your nose and mouth. You should also wear the dust mask if you decide to do any sanding on the OSB. Dust from sanding is

What Preparations Do You Need To Put Drywall Mud Over OSB

putting mud on the drywall

Putting drywall mud over OSB sounds simple enough and hassle-free. What preparations do you need to put drywall mud over OSB?

Copyright protected content owner: and was initially posted on January 20, 2023.

To prepare to put drywall mud over OSB, first make sure the OSB is in good condition. Do not use OSB that is damp, has been frequently exposed to water, or that is warped. Any imperfections in the OSB will be highly visible when coated with drywall mud and will affect the end result of your project.

The next step in preparing to cover OSB with drywall mud is to get the right type of drywall mud. Not all drywall mud is the same. Choosing the right kind of drywall will depend on the type of project you have and your skill in applying drywall mud.

If you are not sure which type of drywall mud to use, here is a simple breakdown of some of the varieties of drywall mud to choose from.

1. All-Purpose Drywall Mud

All-purpose drywall mud is premixed and is versatile for any project. This type of mud is recommended if you are new to working with drywall mud.

2.Powdered Drywall Mud

Powdered drywall mud contains a chemical that reacts when it is mixed with water. The chemical causes the mud to harden quickly and shrink less than all purpose mud. This type of drywall mud is best for the more experienced drywaller.

3.Timed Drywall Mud

Timed drywall mud lets you control how quickly you mud and also how fast the process goes. The time listed on the mud is how quickly the mud dries. You can choose from 5 minutes to 15 minutes or longer.

4.Sanding or Topping Drywall Mud

These types of drywall are designed to be used as a thin top coat that is lightly sanded. It is best to use one of these if you decide to put a coat of paint over the drywall mud, especially if you are wanting a smoother look.

How To Put Drywall Mud Over OSB

confused man standing

Before you begin putting drywall mud over OSB, make sure you are familiar with the process and have all of the tools you need. Read through the following steps to learn how you can successfully put drywall mud over OSB.

Step 1: Prepare Your WorkSpace

Gather all of your materials and personal protective equipment before starting your project. Do not skip this step. Making sure you have all of the items you will need to save you time.

It is also good to prep your actual work area. If you are working in an area that has windows and doors, open them for extra ventilation. Use a drop cloth to protect the floor. Keep a bucket of water nearby for cleaning any messes along the way.

Step 2: Inspect The OSB

Inspect the OSB for any large patches of splinters or knots. Use a hand-held sander to smooth out the rough areas. This will not only affect the finished look but will also help the drywall mud adhere better to the OSB.

If the OSB was previously stored outside, make sure the OSB is not warped or damaged by exposure to water. Do not use the OSB if there are any signs of water damage.

Step 3: Clean The OSB

Cleaning the OSB may seem redundant, especially if you are going for a textured look. However, if you had to do any light sanding of the OSB, the dust will affect the overall appearance and can affect the life of your roller brush, if you are using one.

Step 4: Apply Joint Tape

Similar to working with drywall, joint tape is crucial to reinforcing the joints of the OSB and also to give you a more cohesive look in the end. This step should not be overlooked, especially if you want to paint the drywall mud.

Depending on the type of mud you are using, time is of the essence. Drywall mud can dry quickly and should only be mixed when ready to be used. Before mixing the mud, apply the joint tape over all the joints.

Step 5: Mix The Drywall Compound

Mix the compound according to the instructions on the container or bag. If the mixture is too thick, add small amounts of water until the desired consistency is reached. Remember to only mix enough for what you will use.

Drywall compound that dries out is not reusable and will need to be thrown away. It is best to always mix a small amount and then make another batch if needed.

Step 6: Apply The Drywall Mud

Using your trowel or joint knife, scoop out a liberal amount of drywall compound to coat a small section of the OSB. You want to make sure the drywall mud gets into the crevices of the OSB, filling in any time holes or seams.

Step 7: Repeat

Repeat the above steps until the entire OSB is covered with one coat of drywall mud. Let the mud dry thoroughly before applying a second coat. This usually takes about 24 hours but follow the directions on the compound before proceeding.

Step 8: Sanding

This step is only needed if you find there are patches of uneven wood or high bumps and is purely at your discretion. Once all the coats of drywall mud are applied, the final step is dependent upon the look you are going for.

Copyright article owner is for this article. This post was first published on January 20, 2023.

To put drywall mud over OSB you need to use OSB that is not warped, damp, or showing signs of water damage. Use drywall mud that has a concrete bonding agent. Liberally cover all seams, holes, and bumps. Allow the mud to dry for 24 hours before reapplying.

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ReadyToDIY is the owner of this article. This post was published on January 20, 2023.

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