Painting Concrete and Masonry Surfaces

By Brian Simkins

Use a fresh coat of paint to bring new life to an old basement, an exterior masonry wall, or even a garage floor. When properly prepared, the appearance of a masonry surface can be greatly improved with paint.

What you'll need:

Power Washer: If you are painting an exterior masonry surface, a power washer is the easiest way to remove any dirt, mold or old paint.
Brush: You may need a paint brush to do detail work around windows and trim if you are working on the outside of your home. You will also need a brush if you are cutting in along the walls when painting a concrete floor.
Roller: You will use a roller to do the bulk of the painting. Make sure you read the manufacturer's recommendations as to what size nap to use. You will also probably want to buy at least two covers, as the primer will most likely ruin the first cover.
Primer/Sealer: Most masonry surfaces will need to be primed or sealed before you apply paint. We'll help you decided what you need below.
Paint: Use a high quality product that is appropriate for the setting (i.e., floor paint for floors, exterior paint when outside, etc.)
Floor Texture: This is an additive that is stirred right into the paint. It can be used on floors to prevent slips and falls.
Concrete Patch: Use a simple ready-mix concrete patch to repair any major defects that appear in the surface.
Scraper: If the surface has already been painted, then all of the loose and flaking paint must be removed. While a pressure washer is the easiest way to do this, you will not always be working in a place where a pressure washer can be used. In this case, you will need to scrape it off.
Wire Brush: Use this tool in conjunction with your scraper in those situations where you can't use a pressure washer.
Tri-Sodium Phosphate: Also simply known as TSP, you will use this product to clean the concrete surface before applying any product. It is a cleaner that will remove any grease or oil. This step ensures that your paint will stick well.
Scrub Brush: You will need a scrub brush to use the TSP.
Plastic Bucket: Use a plastic bucket to mix the TSP (it's a powder) with water.
Brush Cleaner: If you are using an oil based paint and primer, you will need mineral spirits or paint thinner to clean your brushes, and most likely yourself.

Clean and Prep the Surface

Once you've done your shopping, it's time to get to work. As with most painting projects, preparation is the biggest key to your success. If at all possible, you will want to power wash the surface. This is the fastest way to remove old paint. Sometimes, though, you may be working inside, or in a place where the mess of a power washer isn't appropriate. If that is the case, then you'll need to tackle that old loose paint with a scraper and a wire brush.

After all of the loose paint has been removed, you'll want to make sure that the substrate is clean. Any oil or grease that may be on the masonry surface will bleed through the paint, causing discoloration, and possibly interfering with the longevity of the paint job. If you have any major defects in the surface that you want to repair, use the concrete patch to make those repairs after you clean it. Refer to the manufacturer's recommendations when trying to assess how long the patch should dry before being painted.

Almost any masonry surface that is going to be painted needs to be both sealed and primed before the paint is applied. The sealer is often clear, but keeps moisture from coming through the concrete. This is especially true in basements, which tend to hold moisture anyway. If you are not sure whether your basement has been sealed or not, tape a piece of plastic kitchen wrap onto the floor and leave it for 24 hours. If the floor hasn't been sealed, you will see condensed water on the plastic wrap that has evaporated up through the concrete.

Buy a quality masonry sealer at your home improvement store and a primer that complements it. Use the two step process of sealing and priming to build a strong, water resistant foundation for your paint.

Painting the Surface

After your sealer and primer coats are completely dry, you may begin applying the paint. Use several thin coats, rather than trying to apply one very thick coat, as paint actually forms a harder surface when thin coats are laid on top of each other. One coat often results is a gummy or soft surface.

When choosing your paint, the most important thing to keep in mind is location. Where is the paint going to be applied? The need for interior and exterior paints is fairly self-explanatory. Additionally, many manufacturers make specific masonry paints. Some are even designated as floor paints, so you shouldn't have a hard time finding what you need. You can also buy additives for your floor paint that will give it a little bit of texture. This material is inexpensive and doesn't change the color, but does prevent the inevitable slip that will occur when wet feet hit a slippery floor.

After your final coat of paint is applied, make sure that you allow the paint to cure for the recommended time. If the paint is on the floor and you don't let it dry long enough, it may dry with footprints that will never go away.

Painting a masonry or concrete surface, whether it be walls or floors, inside or out, can give new live to your home. A space that may once have been dank and dirty can now be bright and clean. You can actually increase the amount of livable space you have just by adding some paint.