How To Finish OSB Garage Walls In 3 Easy & Simple Steps! is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to . The website is also an affiliate of a few other brands.

How Do You Finish OSB Garage Walls?

Your garage, your rules! Unfinished OSB garage walls do have an industrial charm, but you don’t have to settle for the raw industrial vibe. Why not finish OSB garage walls and elevate the looks and transform your garage to a more livable space!

So, how do you finish OSB garage walls? It’s quite easy actually.

  1. Prepare the surface. Sand the OSB walls lightly to remove any rough edges. Fill gaps or cracks with wood filler.
  2. Prime the walls. Apply a coat of primer to the OSB walls. This helps the paint adhere better and give a more even finish.
  3. Paint the walls. Choose a high-quality latex paint. Apply two coats for best results.

Make sure to use good quality materials at every stage!

How To Finish OSB Garage Walls?

OSB is often compared with plywood, for a reason. Both are engineered wood panels. OSB uses wood chips while plywood is made from wood veneers. Adhesives, under high pressure & temperature, bond with the wood to form the panels.

To finish your OSB garage walls using paint you need to PREP, PRIME and PAINT. This is how you do it.

Of course make sure you have all the tools and supplies ready on hand before you embark on your project.

Tools & Supplies Required

  • Orbital Sander with 120 grit or 80 grit sanding pads
  • Paint Brushes & Rollers ( 1 set each for Primer and Finish Coat)
  • Couple of Paint Trays
  • Shop Vac, Portable fans for Ventilation
  • PPE (Dust Mask, Latex Gloves, Safety Glasses) 
  • Oil-based Alkyd Primer
  • Water-based Acrylic Top Coat

STEP 1: Prepping the OSB Garage Walls

Painting OSB can be a bit tricky as it may have a wax coating to make it moisture resistant. Primer or paint will not adhere to OSB, unless the wax coating is removed and the OSB surface roughened up. This is done by sanding.

Use an 80 grit sanding pad if the OSB panel has a wax coating. Otherwise a 120 grit sanding pad will suffice. Use an Orbital Sander such as DEWALT Random Orbit Sander for the job.

DEWALT Orbital Sander

DEWALT Orbital Sander

The DWE6421 5-inch Single Speed Random Orbital Sander with hook and loop pad has a 3-amp motor that delivers 12,000 OPM. The separate counterweight reduces vibration and along with the rubber overmold grip provides comfortable sanding.

A shorter design allows users to get closer to the work surface and the one-handed locking dust bag attaches securely to the sander to aid in dust collection or the user can attach the power sander directly to the DWV010 or DWV012 dust collectors.

You also need to check the moisture content of the OSB panel using a moisture meter such as Tavool Wood Moisture Meter. The OSB is good for priming if the reading is in the 10 to 12% range. In case the moisture levels are high you can reduce it by heating the OSB panels using a portable convection heater.

Sanding of OSB panels creates a fair amount of dust. Wear a face mask while sanding and keep the garage well ventilated. Clean the garage floor often, using a shop vac such as Craftsman 10 gallon portable Shop Vac. You can also use the shop vac with a brush attachment to clean the OSB panels after sanding them.

Finally use a clean rag dipped in white spirit to get the remaining dust out of the OSB panel. Any remaining dust will prevent the primer from getting a good grip on OSB.

STEP 2: Priming the OSB Garage Walls

Primer is always a very important part of paint application. When you finish an OSB garage wall, a good sealer & primer is critical to getting a good finish.

OSB is extremely porous. It absorbs water or paints like a sponge. Water absorption is never good for OSB as it will swell up. Warping, mold growth and termite attacks are a few of the problems that you will face if the OSB is wet or has high moisture content.

So it is best to use an oil based primer (also known as alkyd primer) rather than a water-based primer. A good OSB primer must also have a high %age of volume solids. The primer needs to have a high hiding capacity to cover up the flake pattern in OSB panels.

INSL-X Prime Lock Plus from Benjamin Moore is an alkyd that primes and seals plaster, wood, drywall, and previously painted or varnished surfaces. INSL-X Prime Lock Plus has almost 60% volume solids. This primer can therefore hide the flake pattern of the OSB better than most other primers. 

INSL-X Prime Lock Plus ensures the paint top coat has consistent sheen and appearance (excellent enamel holdout), seals even the toughest stains without raising the wood grain, and can be top coated with any latex or alkyd finish coat.

INSL-X Prime Lock Plus Alkyd Primer

INSL-X PS800009A-01 Prime Lock Plus Alkyd Primer

Prime Lock Plus Primer/Sealer/Stain Blocker is a high hiding, alkyd based, interior primer, sealer, and stain blocker for interior paint primer applications and spot coating outdoor surfaces.

Excellent interior paint primer for plaster, drywall, wood and previously painted or varnished surfaces. It can be top coated with any oil or latex paint. 

Click on this link to download the Technical Data Sheet.

Use a brush for the edges and corners and a roller for the main area of the garage wall. Apply the primer in a W shape with some pressure.

One coat of primer is not sufficient to cover up OSB panels completely. Apply a coat and let it dry for at least 2 hours. Apply the second coat and let it dry for another 2 hours. Hopefully the yellow of the OSB will no longer be showing from under the primer. But if it does, just go for the third coat.

STEP 3: Painting the OSB Garage Walls

The nice thing about INSL-X Prime Lock Plus primer is that though it is oil-based, it can be overcoated with either a water-based acrylic or an oil-based alkyd top coat. Washable latex (aka acrylic) paint is ideal for garage walls.

Acrylic paints come in a range of sheens. Sheen is the level of shininess of a paint coat, once it is dry. Following is a quick guide on the best sheen level for your project.

  • Flat or matte sheen provides great depth of color and is ideal for less-than-perfect surfaces.
  • Eggshell, pearl and satin sheens are light, easy to clean, work great in high traffic areas, and reveal color with a softly polished glow.
  • Semi-gloss sheens are particularly durable and are often recommended for moldings and trim.

Flat white is ideal for garage ceilings as it reflects the recessed ceiling lights and makes your garage look bright. Eggshell sheen interior paint in a color you prefer is great for the walls. The garage walls are bound to get smudged, sooner rather than later. No worries the marks will come off with a sponge dipped in soap water.

Apply a coat and let it dry for around 2 hours. Apply the second coat and let it dry for another 2 hours. Two coats of the acrylic interior paint will result in a smooth, beautiful garage wall.

Thank you very much for reading the post. I do hope you found it informative and useful.

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