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Can You Use OSB For Interior Walls? (How To)

OSB is a construction material that can be used for various purposes. Is it also possible to use it on interior walls?

OSB can be used for interior walls and is a durable and acceptable option for long-term use. As long as you don’t have problems with moisture in the area, you can use OSB without concern about it swelling or deteriorating.

Osb for walls

Most people will compare OSB with plywood. That is especially true when using it for structural use, such as on the wall.

As a contractor, I’ve often run into problems using OSB. It isn’t because of the integrity of the product. It is because of how people view it.

When OSB was first made, it was an inferior product compared to plywood. It got a reputation for being a lower-quality product, and that reputation stuck around.

Is a negative reputation warranted for OSB? Not any longer. New techniques for making OSB have made it just as good and, in some cases, better than plywood.

That being said, if you have a client that wants plywood, it’s better to charge the extra and use plywood. OSB can save money, but it’s not worth getting a bad reputation as a contractor.

Before we consider some of the positive and negative aspects of using OSB for walls, it’s good to consider what type of OSB you will use. Most of it is similar, but a grading system must be considered.

OSB is made from small strands of wood fiber, typically from either Aspen or Poplar trees. It is put together using glue which eventually makes it compact and solid.

Because of how OSB is made, it is sometimes more solid than plywood. It also tends to be a little heavier, which can sometimes be a problem.

As far as the grading of OSB is concerned, there are five different grades to consider. They start at OSB/0 and run through OSB/4.

OSB/0: If you are concerned about the possibility of off-gassing, this is the grade to use. They do not use formaldehyde in this grade, but it is still a high-quality, heavy-duty option.

USB/1: This is also an excellent choice for interior walls. It is a strong material but cannot be exposed to any moisture. If moisture is a problem, choose a higher grade.

OSB/2: For parts of the home that may be humid, such as an exterior garage, OSB/2 or higher may be used. This is a standard option for roof decking, so it can stand up to humidity.

OSB/3: It is not typically necessary to use this grade of OSB for interior walls. It may occasionally be required for exterior walls if it is exposed to water.

OSB/4: This option is used for a heavy-duty wall with considerable load-bearing ability. It isn’t typically necessary for walls because they don’t hold much weight, but if you want to upgrade, this is how to do it.

You can check the market for other options, such as OSB held at the factory for off-gassing or those made from special types of wood. They can make a difference in the construction of your wall.

Most people choose OSB because it is affordable. It is also heavy-duty, so you can use it for walls, floors, and roof decking without worrying about it giving out.

In today’s market, OSB has many of the same benefits as plywood, but there are also some downfalls, which we will consider next.

Should You Use OSB For Interior Walls?

Osb for walls

Even though OSB is compatible with plywood, some concerns may arise when using it on interior walls. Here are a few things to consider so you can plan for them in advance.

Framing – One of the often understated issues with OSB is its limited capacity to span large areas. If you use it in a wall and cover more than a standard stud width, you may need to add additional framing.

The framing issue is not very common when it comes to interior walls. Most of them are framed appropriately, and there will not be a lot of pressure on the wall itself.

At the same time, you want to ensure that you don’t have a flimsy area in the wall that could be problematic in the future.

Formaldehyde – Since you will be using the OSB on interior walls, you must be cautious about off-gassing. Formaldehyde is used in manufacturing almost all OSB, except for grade OSB/0.

There are some ways to get around the issue with formaldehyde and other chemicals. For one, you can purchase the OSB a few months in advance and leave it in a dry and ventilated area.

It may also be possible to reduce off-gassing by finishing the OSB. This is typically done by hanging drywall or tiling, and it will limit how much reaches the breathable atmosphere.

Finally, look for a company that manufactures OSB and keeps it on hand at the factory as it off-gasses.

Off-gassing is a problem with any material you use at home, from carpeting to paint.

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Fire Resistance – It is essential to check with the local authority having jurisdiction (AHJ) for any building code limiting your ability to use OSB. It is widely accepted in almost every area, but you may be limited in some instances.

Check with local building code requirements to see if the use of OSB is acceptable.

Moisture – This is the most common reason people balk at using OSB. It is not a moisture-friendly product.

Before we talk about how moisture can affect OSB, it’s important to recognize that humidity will affect any product, including drywall or plywood. It’s best to keep it as dry as possible, but if moisture does get in the area, it can affect OSB negatively.

OSB will soak in moisture through humidity or direct contact with water. When it does, it tends to swell on the edges, even on cut edges.

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As OSB dries, much swelling will reduce, but it tends to stay swollen on the edges. This problem can result in buckling or noticeable issues in the finished wall.

What Preparations Do You Need To Use OSB For Interior Walls?

Osb for walls

If you are ready to proceed with installing an OSB interior wall, there are some things to do that will make the job a success. Consider these when preparing for the project.

Selecting Material: As discussed above, OSB comes in several different grades. You also need to choose an appropriate thickness and panel size.

When selecting the material, measure carefully to determine how much you will need and purchase 20% more. Overage may be necessary for mistakes or odd cuts.

Protect the OSB: Although OSB can handle a certain amount of moisture, keeping it as dry as possible is best. If you have to have it on hand for an extended time, keep it inside the building so it doesn’t get wet from rain.

Acclimate: It is best to have the OSB on hand for at least 48 hours before installing. Have it in the area where the installation takes place to allow it to adjust to the temperature and humidity level.

Longer acclamation may be necessary if you want to off-gas before hanging. This could be up to three months, but any extra time you allow will limit the fumes.

Clean and Clear: Finally, adopt a clean-as-you-go mentality when doing the work. If you keep the area clean and clear, the work will go faster and you will have fewer problems.

How To Use OSB For Interior Walls

Osb for walls

When it is time to attach the OSB and hang the panels, you might find it relatively easy to do. Here are the steps necessary so you can get through this project successfully.

Measure and Cut: Measuring around any openings or odd bump-outs in the room is necessary. You will have to cut the OSB to fit and put it in place to ensure it works properly.

The more accurately you measure, the less likely you will have a problem with overlaps or gaps. These can be a problem later during installation, so take care of them by measuring them accurately.

Attach the OSB: Various items can be used to attach the OSB, such as nails, screws, or staples. Check with the local building code and the manufacturer of the OSB to see what is recommended.

Finish: One other thing to consider is finishing the OSB. In some cases, the OSB will be covered with drywall, but in other cases, it will be exposed to the home’s interior.

If you have exposed OSB, it should be sanded smooth before finishing. This will give you the best finish and allow you to check for any issues that need to be filled in advance.

You can finish by applying a primer and two coats of paint. If you want the look of OSB, you can use polyurethane.

Try to choose low-VOC options for any finished product. Doing so will limit the fumes and off-gassing.

OSB is an excellent choice for use on interior walls. It provides a strong, sturdy surface that can be finished or covered with another suitable wall surface.

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ReadyToDIY is the owner of this article. This post was published on May 22, 2023.

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