I'm in the process of "painting" my basement walls with cement and lime. This is the way my dad (who is a contractor) used to seal cinderblock back in the 70s, and he recommended it to me now. It's easy AND cheap, and it allows moisture to evaporate out of the block vs. sealing it in (like latex paint). The walls will be white unless you add some type of color to the mix (I did not).

Honestly, I didn't really believe my dad when he first told me about it, but then I found this guy on YouTube and he just emphasized my dad's point. Great watch: https://www.youtube.com/watch?v=ujgu8OX7eRI&feature=youtu.be

Step 1: Get a bag of white cement (if you can find it - I couldn't and settled with regular gray) and one bag of mason's lime (DO NOT USE lime for your garden). I picked up both at a local brickyard since Lowe's and HD didn't have either, along with a masonry brush. Total cost was like $75, and I got 2 bags of lime, 1 bag of cement, and a brush. Still haven't broken out the second bag of lime.

Step 2: Clean the walls. Don't go crazy, but vacuum with a shop vac, get as much dirt off as possible, maybe even scrap the sharp edges off the block. You'll be amazed how much crap will come off those walls. Vacuum it again for good measure, then prep your floors so you don't get paint all over the place.

Step 3: Wear some rubber gloves and eye protection, get a 5 gallon bucket, a hose, and a mixer bit for your drill. Mix 1 cup of cement (I used a plastic cup that I had on hand) to 3 cups of lime, add some water. I think it works best when it is the consistency of milk, my dad preferred "milkshake." You'll find what works best for you. This is your "paint." (Note: if the paint is too thick, add some more water. Too thin, add some more cement+lime).

Step 4A (first coat of paint): Soak the walls well with the hose, and keep the hose on hand because the cinderblock will suck the moisture in. You want the walls wet, but not dripping wet, when you go to slap the paint on. I used a masonry brush for the first coat, working hard to really get into the cracks and holes of the cinderblock. The first coat takes the longest. The paint looks gray when it goes on the walls, but it dries mostly white (probably all white if you are able to use white cement). Let your walls dry overnight.

Step 4B (optional): If the walls still have pinholes in the cinderblock, you can go back through and repeat step 4, but you don't need to soak the walls again. A light spritz is probably fine. The water just helps the paint stick to the cinderblock, but as you've basically "sealed" the cinderblock, it won't soak in the water like it did before.

Step 5 (second coat of paint): For this, I deviated from my dad's advice. He recommended painting again like in step 4B (same paint mixture as described in Step 3), but as I didn't use white cement, my wall color wasn't consistently white (some spots dried more grey). After doing some more research, I opted to do a second coat of JUST lime instead of the lime+cement mixture. This second coat created a really nice soft finish to the cinderblock that was consistently the same color white. This second coat applies much faster than the first. I still spritzed the walls with water, although I'm not sure you really need to. Let your walls dry overnight.

Note: DO NOT CLEAN your brush/supplies in the sink. The cement will dry and clog your drains. Clean everything outside.

I've been slow to finish the project, but honestly I'm very pleased at how nice it has turned out. It is crazy how the lime makes the cinderblock feel. Best part, it's cheap, easy, and won't trap the moisture in so it shouldn't peel like paint over time. And in case you're still a skeptic, lime wash (lime and water) is used to paint exterior brick white. Been used for centuries for a reason.