How can I paint/stain an interior concrete floor?

Question

I have a very lovable aging bulldog who has peed on the wall-to-wall carpet enough that I'm ripping it out. It's over twenty years old anyway.

The subfloor is a concrete slab. My goal is to make the concrete livable. Goals in order:

1. Urine-proof (waterproof). A puddle may sit for five hours before I get home to clean it up. Ideally a bit of soap and water, and no trace is left behind. None.

2. Low VOC products. I've got severe allergies to many/most chemicals. These rooms are my primary living space. I'll test whatever I plan to use, but I need to be very careful so as not to make the place uninhabitable for me. I'm disabled, and am in the main room probably twenty hours a day.

3. Easy application. Fewer products, fewer applications is better, though it's not the primary deciding factor.

4. Something attractive. Least important, but I'm thinking more mottled see-thru stain than I am glossy garage floor. Probably a medium brownish color.

I found some Behr products at Home Depot, but received conflicting information. At this point I'd consider Behr Solid Color Concrete Stain, or Behr 1-Part Epoxy Concrete & Garage Floor Paint.

The Home Depot employee giving me advice said I don't need to prime either product. Just apply to bare concrete. Said either product would satisfy the waterproof requirement.

However, the specs on the products contradict that guidance. Both say "primer required". The stain is "waterproof", the paint is not. Neither product is a "sealer". I'd have thought one of the goals was to seal the porous nature of the floor, at least a 1/2" down, no?

I am looking at priming with Seal-Krete Lock-Down Epoxy Bonding Floor Primer (sorry, I don't have enough reputation to post the link). A big plus for me is that it's the only product thus far with a Low VOC rating. If I understand it, this will seal the pores, and allow the paint/stain to bond properly. It's amber-clear, so it seems that would work under brown-tinted stain, even if the stain isn't completely opaque.

Does this sound like a good plan? Prime with the Seal-Krete, and follow with the Solid Stain?

Initially I wanted a transparent stain, to see the mottling of the concrete. But I had to prime. Since I'm probably priming anyway, would Behr Semi-Transparent Concrete Stain work? My concern is if the urine will puddle, or seep in? The product is not waterproof.

Answer 1

There are (at least) two different types of stains for concrete. One is a surface coating, the other is acid etching.

The former can work, but isn't as durable/lasting. I believe most of the products you get at the big-box stores are more of a top-coat type of stain.

Acid etching is just that, it's a stain containing an acid that actually etches the concrete. This is the typical type of stain you see in home magazines and such. The etching provides a deeper stain that is more durable and not prone to flaking.

I've done the latter, and applying it is super-easy. It's the prep work that can be a chore--namely if you have adhesive on the concrete already. In our case, we has tile mastic, which we had to dissolve using soybean based stripper. It worked great but was incredibly messy.

If you don't have glue to deal with, however, you should be good to go. Order up the stain (lots of places online to get it). You then dilute it per instructions and spray it on the concrete. I used a garden sprayer for this. You then let it sit for a period of time, and then you apply a neutralizer to stop the reaction.

After that, you apply water and mop/squeegee/wet-vac it up.

Then, you apply a sealer of some sorts. Common options are wax-based, polyurethane, and epoxy. I went with poly as it was relatively easy to apply (roll it on). That said, I don't think it was ever truly waterproof. For your needs, you may want to go the epoxy route.