6 Tips for Better Concrete Painting
Concrete has been used by humans for thousands of years, with some of the oldest examples of wells and houses made with the stuff dating back to 6500 BC. Although the ingredients have been refined over time, it’s still basically the same material that those ancient people valued so highly.
Even though concrete’s a really useful substance, it’s not particularly interesting. The endless gray of any random basement or garage is almost enough to make a person go mad. That’s probably why so many homeowners try to paint their concrete floors without considering how concrete is different from other types of building materials. Too often, they end up with the wrong materials or improper preparation, guaranteeing the coating will fail miserably.
Painting Concrete Isn’t Like Painting Your House
Concrete is a tricky substance. Unlike wood that is relatively non-porous, concrete literally breathes and wicks water constantly. This is why you’ll see older homes with miserable paint jobs on their patios, in the basement, or anywhere there’s a lot of concrete. That paint didn’t stand a chance of bonding to the concrete without a lot of help.
But your paint job will be different, that’s why you’re here! Removing old paint from a concrete slab can be a challenging job, but the end result is a glorious floor that twinkles in the sunlight. How about some tips for doing the job right?
#1. Choose concrete stain or dye. One of the main reasons that house paint peels off of concrete is because it doesn’t breathe like the concrete surface. This leads to moisture build-up below the paint, causing adherence to be lost entirely. Concrete stains and concrete dyes are different — they breathe just like the concrete. Stains are made of a blend of acrylic polymers and pigments that react chemically with the concrete surface; dyes, on the other hand, are nonreactive and color the cement when the very small particles penetrate into the surface.
#2. Epoxy garage floor paint is another option. Although it’s much more challenging to apply correctly, if you really want to “paint” the floor, an epoxy-based garage floor paint can be applied to your cleaned and prepped concrete surface. Bear in mind that epoxy takes time to dry and then has to have an additional curing period to harden properly. If you’re dealing with an interior space, you’ll also need lots of ventilation, otherwise the fumes could be your downfall.
#3. Take the time to prep the floor right. This may mean removing old paint with chemical paint remover, power washing the surface or even renting a grinder and roughing up the floor while eliminating old paint. When you’re prepping a concrete floor for painting, it should be just slightly rough, similar in texture to 120 grit sandpaper. Take your time and don’t settle for “good enough.”
#4. Always wash the bared floor thoroughly. With all that old paint gone and traces of various chemicals left behind, it’s definitely time to wash the concrete. Not only does this remove any stray material that might have been missed, you’ll ensure that no unplanned chemical reactions occur (you’re not going to blow up the house, but your paint may fail to adhere). Let it dry thoroughly, for days if possible.
#5. Test for moisture penetration. You’ve cleaned your concrete slab and you’re ready to paint! Except you’re not. You still need to check out the level of moisture penetration coming through the slab. Remember how you can’t use wall paint on concrete floors because it needs to breathe? It’s still breathing. The question now is just how much.
You can test this by covering a three foot by three foot area of the floor with heavy clear plastic sheeting. Tape it down completely and just walk away. Check in with it in a couple of days. If there’s no moisture collecting under the plastic, you’re golden. If there is, you may need to apply a masonry sealer first and retest before applying the final color (ask your paint monger what solution works best in your area).
#6. Priming is vital to success. You’ve probably painted walls and other things without applying a proper primer and it worked just fine, but we’re comparing apples to space ships here. Concrete not only is expected to take a lot harder beating than any random wall, it has all that complicated breathing going on. Skip the primer and you might as well just not do the project at all because you’ll just have to redo it in a few weeks or months.