How To Finish OSB Walls – A Complete Guide

Are you looking to finish your OSB walls but don’t know where to start? Don’t worry – we’re here to help! OSB (Oriented Strand Board) walls are a popular choice for home builders because of their low cost and easy installation.

However, like any other type of wall, there are a few things you need to know before you start framing. In this article, we’ll cover everything you need to know about OSB walls, from the materials you’ll need to the steps you’ll need to take during the installation process. So read on, and learn how to finish OSB walls like a pro!

Painting or sealing the walls first is important because it will keep moisture from getting in and causing damage, as well as make sure that paint will stick to the surface. So, how to finish OSB walls?

The initial step is using polyurethane foam for insulation which can be done by pouring it on top of the sheetrock and smoothing it out with a trowel.

The final step is deciding whether you want your house to look more modern with vinyl instead of polyurethane foam.

So let’s look at the steps in detail.

How To Finish OSB Walls

What Is OSB?

What Is OSB

OSB (oriented strand board) is a type of structural lumber that’s often used in applications where a moisture-resistant and lightweight product is desired. It’s a great choice for high-impact applications like wall sheathing, roofing, and flooring because it can handle a lot of stress without breaking.

Here are some tips on how to finish OSB walls:

  1. Pre-finish the boards with a coating or finish of your choice. This will protect the wood from the elements and make it easier to paint or stain later.
  2. Assemble the wall using joists, rafters, and header/footer assemblies. Make sure the joints between these pieces are tight to ensure a tight wall assembly.
  3. Nail or screw the boards together using appropriate fasteners. Use caution when fastening near edges or corners, as these areas may be more prone to splitting or cracking.
  4. Apply finishing treatments as needed. This will help protect the wood from moisture and other environmental factors, and give it that finished look you’re after.

Types of Finishing OSB

Types of Finishing OSB

There are a few different types of finishing OSB, each with its own unique properties and advantages. Here are the four main types of finishing OSB:

  1. Wet-look finishes – These finishes are applied after the board has been wetted down and are designed to create a “wet” look and feel. They are usually applied to high-traffic areas, such as walls, ceilings, and doorways.
  2. Oil-based finishes – These finishes are applied using a variety of oil-based products, such as varnishes, lacquers, and sealants. They offer long-lasting protection against moisture and fading.
  3. Polyurethane finishes – These finishes are typically low-maintenance and offer a glossy finish. They can be applied using a variety of polyurethane products, such as Spray Polyurethane or Foam Polyurethane.
  4. Cristal clear finishes – These finishes are designed to provide an ultra-clear appearance without the use of harmful chemicals or fillers. They are usually applied using a Brush-On Acrylic Finish or a Roller Coaster Polished Finish.

How To Finish OSB Walls By 4 Steps

How To Finish OSB Walls By 4 Steps

Estimated Cost: $2,000 – $4,000

Time Needed: This project takes one week to two weeks to finish.

Tools And Materials Needed:

  • Tape Measure
  • Stud Finder
  • Safety glasses.
  • Sawhorse or ladder.
  • Paint (exterior latex paint).
  • Paint roller.
  • Safety goggles.
  • Pailing of polyurethane foam (1 gallon).
  • Knife for cutting foam.
  • Safety gloves.

Step 1. Paint Or Seal The Walls

Paint Or Seal The Walls

Painting or sealing the OSB walls is important because it will keep moisture from getting in and causing damage, as well as making sure that the paint will stick to the surface.

This is easily done by brushing on a coat of polyurethane while the sheetrock pieces are still unsealed.

Polyurethane can be purchased at most hardware stores for about $50 per gallon, which should cover a typical home’s 400 square feet.

After using the polyurethane, you need to use a drywall sanding block to smooth out any bumps and help prepare for painting.

This is also important because bumps in the surface of the board, especially smaller ones, will show through the paint and give a rough look.

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You can purchase sanding blocks for less than $2 at most hardware stores, so it won’t be hard on your pocket either.

Before sealing and painting, however, you need to take care not to use any cleaning or scraping products that could damage the OSB boards as they will still be soft at this time. They are best suited for water cleanup only.

Make sure you wait 24 hours after sanding before applying polyurethane, as well as allowing 48 hours after applying polyurethane before applying a second coat of polyurethane or paint.

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Make sure you clean up properly since polyurethane can be flammable if it gets on a heat source, and do not apply polyurethane if there are any signs of moisture.

If you see that your walls have a lot of moisture after painting or sealing then try to locate the source for condensation as soon as possible before it can cause damage.

Step 2. Use Polyurethane Foam For Insulation

Use Polyurethane Foam For Insulation

The next step is probably considered one of the more tedious steps, but it does make quite an impact on the end product. It can be done by pouring it on top of the sheetrock and smoothing it out with a trowel.

You will want to use elbow grease because you are essentially adding thickness to your walls which means more work for you at this stage, but as they say, no pain, no gain! Do not worry.

If your foam is uneven at this point, just make sure that you have enough to cover every square inch of your wall and then you can even it out using a trowel or sandpaper later on.

A mistake many people make at this point is using a sponge instead of a trowel. A sponge will cause the polyurethane foam to drip down, and form pools of it on the floor which looks sloppy, not to mention can make cleanup harder.

Using a trowel also gives you more control over where your foam goes and what thickness it is.

Step 3. Vinyl or Not?

Vinyl or Not

The last step involves deciding whether you would like your home to be modern-looking. It can be vinyl instead of polyurethane foam insulation.

While this may seem insignificant, it does influence how your house looks overall. So keep in mind that any changes might require re-sanding before applying paint.

If your walls are already insulated with polyurethane. Then you cannot use vinyl as they do not go together well since one is installed while soft. And the other is applied after it hardens.

A mistake many people make at this point is thinking that they cannot finish their insulation if they plan to wallpaper or paint over it later.

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This is not true as long as you first put a coat of polyurethane on top of your foam insulation. Before moving on to the next step, which in most cases will be painting.

For walls that will only have one layer of drywall and no wallpaper or painting. Then vinyl might be more suitable. Because it gives them a different look than polyurethane foam does, even though both do similar jobs.

Vinyl can either be glued to the OSB boards or installed with small nails. So keep this in mind when deciding how you would like to finish your walls.

If you chose to use vinyl and would like to install it in a way that is similar to how polyurethane foam is installed. Then you will need nails or small tacks first and then glue the vinyl over them.

Installing vinyl this way means that the surface of the OSB boards will not be damaged by the nails even though there are quite a lot of them, which can be an advantage if you ever plan on repainting your house as they might not show through any paint.

This process works best for smaller pieces of vinyl, such as those for trimming windows or doors, because larger pieces may rip when attempting to remove them after following these steps.

Making sure you have sealed all areas where moisture can enter is very important because if left untreated, the water can have a reaction with the foam insulation, which might cause it to soften and become much easier to damage, especially in places where there are nails or screws.

If you find any areas inside your walls that are problematic, then try to sell them as well as you can using caulk since this should be fairly easy to do and will keep moisture from damaging your home.

The last step also involves making sure all operations have been cleaned up thoroughly before applying the second coat of polyurethane or paint.

Make sure you clean up properly since polyurethane can be flammable if it gets on a heat source, and do not apply polyurethane if there are any signs of moisture.

But, you should be aware that using Vinyl instead of polyurethane will take a lot more work as well as money.

Vinyl can be purchased at any home improvement store for about $30 per square foot, and you will need 2-3 coats in most cases.

What many people do not know is that they can actually paint over the vinyl if they choose to, so it gives them the option of changing up their decor later on down the road.

Step 4. Completing The Process

After you have covered every square inch of your walls, you will need to wait at least a day. And then use a drywall sanding block to smooth out any bumps and help prepare for painting.

You should also take this time to caulk up all of the small gaps. That can be done by using pre-mixed silicone caulking. Or by taking some liquid nails and glueing them in place with your fingers.

If you would like to try vinyl instead of polyurethane foam. You will want to put on 4 coats over a period of 7 days since it dries so slowly.

The first coat is typically laid down with glue rollers. That is widely available at hardware stores (about $0.50 per foot.)

The second coat is traditionally brushed on. And helps to even out the first coat with a rolling technique (about $1.00 per foot).

After this, you will be ready for your last two coats of paint that are about $0.75 and $1.25, respectively.

Once all of this is done, you should have a nice-looking wall that will provide good insulation as well. But keep in mind that no matter what material you decide on.

It should not take away from the importance of sealing the walls inside. And outside since moisture can cause damage down the road.

A trusted contractor such as Whiteside Home Improvement would likely do a very good job at finishing OSB walls. So look them up if necessary!


You should now have a good understanding of how to finish OSB walls. It is important to fully understand the process before attempting it. Because if done incorrectly, you could end up with an unfinished wall that needs to be removed and repaired.

Although it is better for outdoor use, many people have had good luck with installing OSB walls inside their homes.

Just make sure that you take into account how moisture can enter your walls in this case. And seal up all areas which are worrisome.

If you do this step properly, you will be able to enjoy having a homemade of OSB. You shouldn’t worrying about how it looks or how well it works.


1. How Do You Seal OSB Walls?

Answer: Sealing OSB walls is a fairly simple process. It needs to be done within the first few days after they were installed.

The OSB is often installed with nails. Or screws due to the ease of installation that it provides. So this should be taken into account when sealing the walls.

2. Can OSB Be Used For Interior Walls?

Answer: Yes, OSB is typically used for interior walls and ceilings. It gives the home a more modern feel while also providing good insulation throughout the home.

3. How To Paint OSB Board?

Assuming you are painting OSB, you will need to prepare the surface and prime it.

To prepare the surface, first clean the surface with a detergent and water solution. Make sure the surface is completely clean before starting your painting.

Next, apply a primer to the surface. Primers are available in a few different types, each with its own specific application instructions. Follow the instructions on the primer packet to apply it evenly to the surface. Let it dry for at least two hours before starting your painting.

To start painting, use a brush or roller to apply the paint. Make sure to use a low pressure and keep your brush moving constantly in a circular motion to achieve a even layer of paint on the OSB. Let the paint dry for at least two hours before removing it with a sandpaper or cloth.

4. Suggestions For Finishing OSB Floor And Walls?

There are a few things that you can do to finish your OSB floor and walls. Here are a few of my favorites:

  1. Paint – A great way to finish your OSB floor and walls is to paint them. This will give them a nice, finished look and will protect them from moisture and other damage.
  2. Apply a sealer – Another great way to finish your OSB floor and walls is to apply a sealer. This will help protect them from moisture, light, and other elements.
  3. Stain – If you want a more natural look for your OSB floor and walls, you can stain them. This will give them a more stain-resistant finish that can last for years.
  4. Use an adhesive – If you want to use an adhesive to finish your OSB floor and walls, be sure to use one that is water-resistant. This will help protect the adhesive from moisture and other elements.

5. Why Cover Garage Walls?

Covering garage walls can be a great way to protect your vehicles from the elements and thieves. Not only will it help keep your cars clean and free of pollen and other harmful particles, but it can also help to keep thieves from accessing your vehicles.

By covering your garage walls, you are also preventing them from being able to see what is inside – making it harder for them to steal anything.

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