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How to Clean, Prep & Coat Garage Floors

With PPG, coating concrete floors is easier than ever

How To Clean, Prep & Coat Garage Floors

Painting a garage floor is a good idea when it’s done correctly. A person can clean their floor with much less effort due to the smooth painted surface. Adhesion of oil, mold, water, chemicals, mildew and other staining materials can be prevented due to the type of paint selected to paint the garage floors with.

How To Clean, Prep & Coat Garage Floors

Getting Started

How do you know if a garage floor is suitable for a floor coating? There are a few things to look for to check for coating suitability, and these are:

  • Moisture
  • Applied sealers
  • Additives to the concrete
  • Contamination

If there is a moisture problem, it's very likely that you are not going to be able to coat the floor properly. If there are visible white crystals or white powder on the floor, then the moisture has seeped through the surface and formed a layer so no paint will stick to it. If the floor is damp or the air is musty, then the paint will eventually fail and not stick.

How To Clean, Prep & Coat Garage Floors

Checking For Moisture

A plastic sheet test can check for moisture on the floor. Tape an 18 by 18 inch square piece of clear plastic sheeting to the concrete floor on all four sides. Do not place your test in direct sunlight. If condensation is found under the plastic after 16 hours, or if the surface is visibly darkened, then it’s considered too wet. Cold weather and temperature swings may also affect the test. If you pour some water on the floor and it beads up or sits on the floor for a long time, then the concrete likely has either a sealer on it or oil contamination. If the concrete is saturated with oil, then the floor may never be successfully coated.

How To Clean, Prep & Coat Garage Floors

Cleaning & Prepping the Floor

You may use an alkaline cleaner or commercial de-greaser such as Dura-Prep 125 to clean contaminated floors. Paint will not stick to wax or silicone based sealers. Certain additives can cause a coating to fail no matter how well you prep the surface.
Why is proper surface prep so important? It can take a while for any damage to appear on the floor due to improper prep. If that's the case, the floors will have to be refinished costing valuable time and resources. Three ways to properly prep a concrete floor are:

  • Shot Blasting
    • In the shot blasting process, the surface is blasted with small steel shot pellets, similar to BB pellets, at extremely high speeds. Shot blasting is not practical or affordable for home owners or residential painters.
  • Acid Etching
    • In the acid etching process, an acid and water solution is applied and a chemical reaction etches the concrete making it porous enough to accept the coating.
  • Grinding
    • A mechanical grinder is used to rough the surface and make it porous enough for the coating to bond. Grinding gives the surface a look similar to acid etching, but it’s much safer and easier, thus making this a good choice for home owners or residential painters.

How To Clean, Prep & Coat Garage Floors

Painting The Garage Floor

The concrete floor should have the feel of 80 to 120 grit sandpaper before a coating is ever applied. For a solid color finish, you can apply a solid color stain or epoxy. For a colorful finish, you can apply a multi-layered decorative flake floor finish, but it may require more detailed training. Knowing how to clean garage floors, prep the surfaces and knowing how to paint a garage floor is essential to a professionally coated garage floor. It can make a big difference in the appearance and performance in one of the busiest areas of a home. The painted floors look beautiful, and when professionally applied, the coating performs well.

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