Oriented strand board (OSB) is a building material used on many projects. It is frequently used as an underlayment, such as for roofing or flooring but can it be used as siding?
OSB can be used as siding in substitution for other materials, such as vinyl or wood. When it is prepared properly and finished, it can stand up to some abuse from the weather.
The primary reason why people choose OSB for siding or any other use is that it is less expensive. There are actually a number of reasons why you would not want to use OSB, and we will consider them in this article as well.
When it comes to using OSB for siding, however, it’s important to consider the reason why you are installing siding in the first place. Siding is there to protect the interior of the walls and to keep the weather on the outside.
OSB can do a suitable job and there are actually some types of OSB that are better suited than others. We will consider those next.
The first type of OSB that should be considered for use on a siding job is moisture-resistant. Be aware that OSB is not waterproof, even if it is marked as such.
The fact that OSB is marked as moisture-resistant, however, means that it is able to stand up to the weather better than other types of OSB. It may be more expensive, however, which can defeat the purpose of using OSB rather than plywood or another type of building material.
It’s also important to understand the nature of OSB. When compared to plywood, it really doesn’t stand up as nicely to water in most cases.
OSB is made up of many strands of wood that are glued together. Plywood, on the other hand, is made of thin sheets of wood that are glued together.
Is there a benefit to using plywood other than OSB for siding? It really depends upon the needs of the person doing the job.
PRO TIP: OSB has been proven to be just as suitable for construction as plywood by InterNACHI. They each have their strong points but when comparing the two, you will find that both are good products
I have had a number of clients that insisted on using plywood for siding, even when OSB would’ve been more than suitable for the job. In this case, it was really a matter of aesthetics.
The client gets what the client wants, and if they want to spend more on plywood, so be it. It doesn’t mean that OSB is an inferior product, it just means that appearance matters.
One other thing to consider is the possibility of using OSB which is tongue and groove. Although it is not necessary for a siding job, it can have benefits.
The tongue and groove OSB panels fit together nicely on the edges, so it has more of a watertight fit compared to regular OSB. In addition, if the OSB is exposed on the outside, it will look better when finished.
Should You Use OSB For Siding? (Any Problems To Look Out For)
Although it certainly is possible to use OSB for siding, there are some issues that need to be considered. These issues may make a difference in your decision to use OSB or not.
Moisture: The most important consideration for using OSB for siding is moisture. OSB will soak in moisture and will retain it for an extended amount of time.
Just by way of full disclosure, plywood will also soak in just as much moisture and will also retain it while it dries. The difference is, OSB will swell on the edges while plywood tends to swell everywhere.
When OSB dries, any swelling on the edges will not reduce. It will maintain that shape, which is why you need to be very cautious when using OSB for siding.
Performance: Although OSB will last for a considerable amount of time when it is prepared properly and cared for, it is still going to have a limited lifespan. You may eventually find that you have to replace OSB, perhaps even sooner than plywood or another type of building material.
If you are using OSB to save a few dollars, you may end up spending more in the long run because of that simple fact. Count the cost before you start building.
Resale Value: Not everyone is going to be happy with your decision to use OSB for siding. If you are doing it for your own benefit, all is well and good but if you are trying to sell the home, you may not get the biggest resale value on the market.
People tend to look at OSB as an inferior building product. Even though it has been proven to be just as good as plywood, it is still not going to do as well on the market.
Code Compliance: Before you do any type of building project, it’s best to check with the Authority Having Jurisdiction (AHJ). In many communities, OSB may not meet the building code.
Copyright protected content owner: ReadyToDIY.com and was initially posted on 2023-06-01.
If you take the step of getting a permit before you start building, which is always recommended, this will likely be caught in advance. On the other hand, if you are just doing a weekend warrior project and trying not to get a permit, you could end up in some hot water.
The AHJ could force you to remove the OSB or they may make you do something else to bring it up to compliance. At the very least, you could end up with a fine.
What Preparations Do You Need To Use OSB For Siding
If you have made the decision to move ahead with the project of using OSB for siding, there are some steps necessary to prepare the project in advance. If you prepare things properly, you are more likely to be happy with the overall project.
Prepare the Surface – One of the first things to do is to prepare the surface for installation. This may include removing any nails or perhaps some old wood that may be in the area.
The real key to preparing the surface is to remove everything that would stop the board from being applied properly. This could be anything from nails to dirt.
Copyright article owner is ReadyToDiy.com for this article. This post was first published on 2023-06-01.
As you will see, you will be using an adhesive to apply the OSB as siding, so dirt will stop the adhesion from working well. In addition, any lumps or bumps under the OSB are going to stop it from installing flush to the structure.
Moisture Barrier – When most of us think about moisture affecting OSB siding, we think of it coming from the outside. Although it certainly can come from the weather, it can easily come from the inside as well.
It is important to protect the OSB on both sides, so applying a moisture barrier in advance is an important step. By wrapping the structure in some type of moisture barrier prior to installing the OSB, you keep moisture from getting to the back of the OSB.
If moisture does get to the back of the OSB, it will likely rot away over time without being noticed until it is too late.
Clean Work Area – Take the time to clean the work area thoroughly before getting started. Not only is a clean work area a safe work area, but it will also make the job much more pleasant and things will go faster.
At this point, you are prepared to install the OSB. In our next section, we will discuss how to do it properly.
How To Use OSB For Siding
You should be looking at a clean and smooth-running worksite at this point. Everything is ready for the installation, so let’s get started.
1. Seal and Prime: This is a step that should never be skipped. Even if the OSB is rated for outdoor use, it is still going to experience some swelling when exposed to water.
Sealing and priming the OSB may not be a perfect solution, but it is going to help to keep it from swelling and getting ruined. The way that you do it is important to consider.
The reason why we ask you to seal and prime the OSB before you install it on the siding is because of the edges. Don’t neglect to get those edges sealed or you could end up in trouble.
Remember what we discussed earlier, OSB tends to swell on the edges. If you allow the boards to soak in water on the edge, it is more likely to swell as a result.
You should also use a primer that is ideal for the type of paint you will be using. Yes, we do suggest that you paint the OSB after it is installed.
For water-based, acrylic paint, use a water-based primer. For oil-based paint, use an oil-based primer.
One coat of primer will suffice. Using more than one coat of primer may sometimes be counterproductive.
2. Measure and Cut: Make sure you get accurate measurements and if you are using tongue and groove OSB, which we recommend, you can measure exactly. Otherwise, you may need to leave a slight gap for expansion purposes.
OSB is relatively easy to cut. Most people will cut it using a circular saw, so you need to take the measurement from the guard to the edge of the saw blade into consideration.
It is best if you make a jig so you can put it on the OSB, automatically getting your right angle and having the measurement in place to account for the width of the circular saw guard.
3. Adhesive: Although you will be using screws to install the OSB, it is also a good idea to use some good construction adhesive. This will help to hold the OSB in place securely, even if the screws should fail.
Think of the adhesive as being a second layer of protection. The screws are going to do their job, but the adhesive forms a very strong bond when it is applied properly.
4. Finishes: The final step in the process is to finish the OSB. Most people will want to apply a coat of paint.
Paint does more than make the OSB look better, it also adds a layer of protection. It is a step that should not be skipped for outdoor use.
OSB makes suitable siding in outdoor environments. When it is properly sealed and maintained, it can last for many years.
ReadyToDIY is the owner of this article. This post was published on 2023-06-01.