How to Select the Right Coating for Your Garage Floor
Eric Olson | August 22, 2017
Credit: Decorative Concrete Kingdom / CC BY 2.0
Source: Seal-Krete
Protecting garage floors with a coating, paint or sealer can preserve and improve the lifespan of a new floor or restore an aging surface to full functionality. A wide range of products is available offering a variety of protective features, including dust-reducing abrasion resistance and mold and mildew mitigation. Sealing the concrete surface shields it from dirt, oil, grease, salt, chemicals and automotive fluids like gasoline, antifreeze or brake fluid. Protected floors gain resistance to stains and an attractive finished appearance.
Surface Preparation
Before a protective coat is applied, proper surface preparation is essential for achieving a good result. All dirt and debris should be swept or vacuumed up. The floor should then be scrubbed clean with a stiff-bristled brush using detergent or degreaser to wash any oil or stains away. A pressure washer can help with built-up grime.
Acid etching can be applied to roughen the surface, opening pores in the concrete that allow a paint or coating to penetrate and adhere to the floor. If the concrete was previously sealed, sanding or sandblasting the floor creates a coarse surface for the new coating to adhere to. Concrete primer forms an ideal base to improve top coat uniformity and adhesion to previously painted or bare floors.
Epoxy Coating
Epoxy floor coatings are two part systems that offer a high level of surface protection. Comprised of a resin and a hardener, the two components chemically react when mixed together, forming a cross-linked molecular structure during the curing process that protects the concrete underneath.
Epoxy floor coatings come with varying amounts of solids. Products with higher solids content cost more and have a thicker consistency that is harder to spread but that cover more area per volume of product purchased. The final applied dry film thickness of a product with 40 percent solids by volume will be less than half the wet film thickness of the uncured coating. This is due to the evaporation of the solvent.
Epoxy coatings come in a variety of finishes such as gloss or matte satin and a range of colors. Colored acrylic chips can be added to create a pleasant aesthetic.
Source: Decorative Concrete Kingdom / CC BY 2.0Acrylic Floor Paint
Latex acrylic concrete paints are cheaper than epoxy coatings but they are not as durable. Acrylic floor paints are more susceptible to wear, chemical erosion and peeling from hot tires. Some acrylic floor paints contain a percentage of epoxy that improves the durability of the product, making them more suitable for applications like garage floors.
Floor Stain
Staining a garage floor results in a translucent finish that enhances the appearance of the surface by creating a marbled look. Stains can be either water-based or acid-based. Water-based stains are easy to apply and can be more environmentally friendly, although they are not as long-lasting as acid-based stains. Applying concrete stain does not provide a high level of surface protection; a sealer should be applied in areas that are more heavily trafficked.
Floor Sealer
Some concrete sealers are formulated to be applied directly to clean, bare concrete. Others are intended to be used as a final protective top coat over painted concrete.
Acrylic sealers and siliconate sealers both seal and protect concrete from moisture, stains and abrasion. Siliconate sealers penetrate into the pores of the concrete and react with its free lime to form a barrier against moisture and reduce the dust created by abrasion and aging of the surface. They also impart surface strength and minimize scaling and spalling. Using a densifier sealer with sodium silicate or lithium silicate increases surface strength and hardness, maximizing abrasion resistance.
Top Coats
Applying a top coat over concrete that has been painted further seals and protects the surface, increasing the life of the coating. Polyurethane top coats are highly resistant to abrasion, chemicals and ultraviolet radiation from sunlight. Epoxy can also be used as a top coat sealer but creates a harder surface that can lose its glossiness as sand and dirt particles create abrasions. With its high dry film thickness, it is better suited as a base coat than polyurethane. Polyurea and polyaspartic top coats offer similar benefits to polyurethane sealers. They also have fast cure rates, although they are pricier.
Resources
I was thinking of putting an epoxy finish on my garage floor. After talking to people that have done it - both DIYs and having it done - they said the coating is thicker and there is less blistering. But, considering the investment, one would like to do it right.
There are also some very high spec water based paints and the price is dropping due to increased uptake. They are non-toxic and the water cleanup is a great time and cost saver. Excellent for floors as if applied after waterblasting the key is outstanding. The primers can be topcoated with anything.
Phoenix Paints in Australia is one brand I have used and been very impressed with.