This article examines OSB, what it is, what its uses are, its pros and cons, how we can make it look like drywall, and why and when we would do this. Drywall mud is the go-to product to make your OSB look like drywall. Here is a step-by-step guide on how to accomplish this.
What Is OSB?
Oriented Strand Board (OSB) is a manufactured wood panel constructed from rectangular wood pieces and heat-cured adhesives. It is waterproof and versatile, like plywood in strength and performance, and resists distortion and warping.
How Is OSB Made?
OSB is manufactured from various species of trees such as poplar and aspen and makes use of trees that are unsuitable for planking, including those that are crooked, knotty, and of small diameter.
The wood is cut into strands 8-15 cm long, mixed with waterproof resin, and interleaved into thick matted sections. These sections are then bonded with the use of pressure and heat. The final product is solid and uniform, very strong and water resistant. Manufacturers may make various OSB merchandise for different applications.
OSB is chemically treated to improve its resistance to fire, and decay and is completely waterproof if the correct resins are used in its manufacture. Reputable manufacturers test their products to ensure that they meet the specifications set out by the country’s borough of standards.
What Is OSB Used For?
OSB is primarily used in the construction of light-frame wooden buildings and other projects. It may be used for roofing, floor, and wall sheathing. As it is strong and stable and won’t warp and resist pressure from wind and seismic activity, it can be used for other uses such as RV fabrication, cargo-van panels, industrial containers, pallets, and furniture manufacturing.
As mentioned above, OSB is strong, stable, versatile, and has numerous applications. Compared to other similar products like plywood, it can be manufactured into larger panels. OSB is lightweight and durable. Its quality is more consistent than plywood due to the lack of core voids and will not delaminate. OSB is also cheaper than plywood.
Again, compared to plywood, OSB is heavier and may retain moisture for longer. Unless it has been well treated with water-resistant resins and waxes, it still tends to swell when damp. Plywood normally swells evenly and then retains its original shape when dry, whereas OSB remains deformed due to its higher compaction ratio from its date of manufacture.
Although the resins used now are more compatible with moisture resistance, OSB still tends to swell on the edges, especially if it has been cut. Many people still consider it a sub-standard product and may assume that their builder is cutting costs at the expense.
Can OSB Be Made Look Like Dry Wall?
Whether your plan is due to practical or aesthetic reasons, according to many sources, drywall mud is your primary product. Whether thickly or thinly coated onto OSB, it helps to seal and harden the board. It is a cost-effective option and requires little sanding.
It is essential to remember that time is of the essence when using this method, as the mud must be completely dry before adding each coat of paint. If you do not have the time or patience, do not use this method. Another important criterion to remember is that the OSB you use must be completely dry.
The water content in the mud will not harm the OSB, which is already water-resistant. However, you do not want the mud to be too watery, due to OSB’s tendency to swell and it will prolong the drying time between coats. You may need to touch up holes or cracks periodically.
Tools You Will Need
Ensure you have the following in hand:
- Sheetrock mud
- Concrete binding agent
- Joint Knife
- Paint roller
- Flexible hold joint tape
- Personal protective equipment i.e. gloves, N95 dust mask, eye protection
Drywall compound comes in an extremely fine powder that is easily inhaled, and the chemicals can be dangerous to the mucus membranes of your nose and mouth.
A little attention to detail before you start will make the process less complicated and hassle-free. Check the following:
- that the OSB is in good condition. It is not warped or damp or previously exposed to water. Flaws in the OSB will be noticeable when coated with drywall mud.
- That you have the correct type of drywall mud for your project. Not all products are the same.
- Spend some time learning about the process before beginning.
Types of Drywall Mud Suitable to Use Over OSB
1) All Purpose
This product is premixed and suitable for most projects. Consider purchasing this if you are new to working with drywall mud.
This product is best suited to experienced workmen. It contains a chemical that reacts with water which produces a quick drying layer. It also shrinks less than all-purpose mud.
The time stated on the packet is between 5 and 15 minutes or longer. This time is how quickly it takes for the mud to dry. Again, consider the longer times if you are inexperienced with drywall mud.
These products are best suited for thin topcoats that may be lightly sanded. Sanding produces a smoother finish especially if you plan to paint over the drywall mud.
Before starting your project, ensure that you have all the tools you need and are familiar with the process.
Step 1: Prepare your workspace.
Apart from having all your tools close at hand, you may want to use a drop cloth or protective floor covering. Open windows for ventilation if you are indoors. Ave a bucket of water, rags, or sponges to clean up messes.
Step 2: OSB Inspection
Inspect the OSB board for imperfections, knots, or splinters. Lightly sand down any rough areas. This will help the drywall mud stick to the surface better. Brush or wipe down to remove dust. Do not use the OSB if it has been water damaged, is warped, damp, or swollen.
Step 3: Apply Joint Tape
Reinforce the joints of the OSB with joint tape. This will give a better finish especially if you are planning on painting the surface.
Step 4: Mix The Drywall Mud
Depending on the type of compound you are using, time is important to only mix the mud when you are ready to apply it, especially if it is one of the quick drying varieties. Mix the product according to the instructions on the bag. If it is too thick add small amounts of water until you reach the consistency you want. Once drywall mud dries and hardens it is not reusable, so only mix enough for immediate use. Rather to have to mix a second batch than to waste it.
Step 5: Applying the Mud
Apply the mud using a trowel or joint knife. Use enough to coat a small section of the OSB, ensuring that you pay attention to holes or crevices in the OSB. Keep working until the full board is covered. Allow to dry. This may take up to 24 hours depending on the type of mud you are using. Repeat the above steps for second or third coats.
Step 6: Sanding and Painting
This step is only applicable if there are uneven patches or bumps, and to your liking. If you are going to paint, ensure your surface is smooth enough.
Step 7: Spray On Dry Wall Mud
It is possible to use a thin mixture of drywall mud in a spray gun according to a responder when a DIY enthusiast asked this question on Reddit. If you are considering this route, do your homework on the most suitable equipment and product to use.
OSB is a product with both advantages and disadvantages. Modern methods of manufacture ensure that it is water resistant, of good quality, and cost-effective. The leading way of making it resemble drywall is by using drywall mud.
This has the added advantage of sealing and hardening the OSB. There are various types of drywall mud on the market and the project and your experience are criteria when choosing which to use. Ensure that you protect yourself from harm when using this product. If you take the time to prepare well and learn the process, you should achieve the finish you want.
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