How To Finish OSB Garage Walls In 3 Easy & Simple Steps!

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How Do You Finish OSB Garage Walls?

Do you have a garage with OSB walls? You may be tempted to not even finish it. OSB has a raw industrial look & feel, which is possibly good enough for a utilitarian garage. However, if you want a better looking and more livable space, you do need to finish your OSB garage walls. But how do you finish OSB garage walls?

You can finish OSB garage walls as a DIY project. Painting OSB is possibly the best option. Painting OSB is a relatively simple job provided you understand OSB, surface preparation, priming & sealing and paint application.

How To Finish OSB Garage Walls?

Of course, you must use good quality materials too!

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

Tools
  • 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) 
Supplies
  • Oil-based Alkyd Primer
  • Water-based Acrylic Top Coat

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.

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.

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 you must only 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.

  • High-hiding, multi-purpose alkyd primer sealer
  • Superior adhesion to glossy surfaces
  • Prevents bleed-through
  • Excellent enamel holdout
INSL-X PRIME LOCK PLUS for OSB Garage Walls

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.

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.

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.

Benjamin Moore has an excellent range of interior acrylic paints. You could choose any of them and come out a winner!

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.

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

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