How to fix peeling paint on a concrete floor
– adhesive (I used leftover construction adhesive that was too thick to use as a paste by itself).
– paint – primer is not necessary with this type of paint. You only need the glue and color layers. I used latex paint from a local hardware store for this project. Preferably, you should use a product that is low in VOCs and non-toxic because it will be exposed to children’s hands touched by mothers’ hands that may not be completely sanitized after using the toilet [in other words, you don’t really want to absorb whatever chemicals are in the paint].
I assume here that you have already removed all loose/peeling bits of paint using your preferred method. In my case, I used a scraper blade because it was easy for me to score the peeling fragments off just enough to get rid of them without scratching too much concrete. If there were still adhesion issues, I used a chemical paint stripper to remove the last bit. Make sure all bits and bobs are off the floor before you start with your adhesive application.
What I did: Most people use epoxy or urethane adhesives when fixing peeling paint out of convenience since their primary consideration might be aesthetics/appearance rather than strength.
This means that they have better adhesion properties than standard construction adhesive, which is designed to adhere to relatively weak surfaces like drywall, not concrete.
I only had the regular construction adhesive, which is too viscous for easy painting because it was leftovers from another project, so I could not use it by itself. To compensate for this, I just added some fine sand (from ~$2/bag at local hardware stores) into the mix to improve its adhesion to concrete while still keeping it thick enough that it did not run everywhere when applied.
Suppose you have access to an epoxy or urethane adhesive (those are stronger and cheaper). In that case, you can definitely use them instead of this method without sand, but make sure you completely seal off your garage/room if you do because strong adhesives have a tendency to emit hazardous fumes when setting. If you can’t, don’t use epoxy or urethane.
I mixed the fibers in with the adhesive using a stir stick and my hands. Basically, just scoop up some of everything from your mixing container, put it on top of your floor slab, and rub it around with your hands until you have evenly distributed all material. You may need to add more adhesive if anything doesn’t seem very sticky/stays messy after rubbing them into the concrete.
In this area, I happened to get extra glue that overflowed during the application because I didn’t mix enough initially (not sure why). Since there was too much for me to simply swipe away while not removing any primer, I had to remove the excess with a bit of water (the glue would not set if it was still wet).
To make sure your floor isn’t too sticky for the paint to stick well later, you should then wipe it dry using some paper towels/rags.
I only had a mini roller and 1/2 sized tray, so I just made do with what I had since this was just a test area (~$15 in paint supplies). If you don’t mind spending more money on supplies that can be used multiple times (and probably will be if you take good care of them), get yourself one big roller and 2 1/2 sized trays instead. It doesn’t matter too much which brand/type of paint you use as long as it will dry to a hard surface (most latex acrylic paints can do this, but not all). I chose the cheapest paint I could find (~$6/gal) at Walmart because I wasn’t too concerned with its quality.
What you could try: Even though I only had plain construction adhesive and sand to use for my mix, there are definitely other options that should work well too.
You might be able to get better results by mixing in some epoxy resin if you know how to apply it properly and have access to it. If you don’t care about the industrial look of fiberglass mesh tarps, they also have incredibly high tensile strength, so they can easily provide more support than what’s needed for just holding up your floor.
What ended up happening: The paint didn’t dry to a rock hard finish, but that’s what I expected with the cheap paint I picked out. It was very smooth after drying even though it looked bumpy while wet (I’m not sure if this is because of the stiffness/cracking of the concrete, although the fiberglass mesh might have helped with this too), which made it easy to sweep any dust or particles away without having them stick around. I had to wait another week before the paint got hard enough to apply my second coat without disturbing it. The paint held up well with no chipping whatsoever (even though this was only a test area), and the floor is now ready for whatever use you want (the paint won’t chip like normal, but it can still be scratched).
So next time you have some spare tarp fibers sitting around or just happen to run into them at your local hardware store, don’t throw them away! A mixture of fiberglass mesh tarps and construction adhesive makes an incredibly cheap/effective solution for creating a super smooth floor surface on top of the concrete so you can easily walk across it barefoot or drag furniture around without worrying about damaging anything.