Should I seal, waterproof a concrete basement floor before painting?

Question

What is the best sealer/waterproofer to put on a basement floor that I just want to paint. New construction, no water problems, but washer & drier & water heater are in basement and add to moisture in the air.

Answer 1

I'd suggest one of two options:

1. Epoxy paint (typically labeled as 'garage sealer')
2. Acid Stain and seal

I much prefer the look of stained concrete to painted concrete, but that's obviously a personal choice. We stained our concrete basement floor when we finished it and sealed it with a off-the-shelf concrete sealer.

Answer 2

If it's new construction you shouldn't need to put down a waterproof layer before painting the concrete floor. Below the slab should be a waterproofing system that prevents moisture coming up from below.

If you wish to double check that rising moisture is going to be a problem, take a look at this answer here on SE.

• Before painting, prepare the slab the best you can (ie Clean and dust free), being as it's new construction it shouldn't be a difficult task as there shouldn't be any grease, oil, etc that needs to be removed before painting.

• For best results it's best to seal (and prime) the concrete before painting in your chosen colour.

  • From your local DIY store or specialist paint shop, you should be able to get a good quality concrete sealer and a separate primer that's compatible with the sealer. Using a two step process like that will give you the best surface to paint on ie:

  • Achieve a high quality finish that should last for years and years...

• When applying you chosen (concrete floor appropriate) paint, it's best to apply in (multiple) thin layers, following the recommended drying time between each coat as given on the paint can, and build up those layers to a high quality finish, instead of trying to apply one thick coat...

Below are a couple of questions here on SE that you might also wish to have a read through (as I believe they contain some useful and relevant information to your situation):

• Should I use a subfloor for a finished basement's floor?

• Is floor paint on concrete purely aesthetic or actually functional?