If you think that's expensive, wait until he sees the bill in two years when he pays me to come and fix it... hahaha I'm kidding. You're right. My method would be expensive.
This is how you will feel when you realize you've created silica crystals from trapping moisture in the concrete and...
If there was mold, that means there was moisture in your concrete. If that's the case you need to do a moisture barrier test (taylor tools concrete moisture vapor emissions test). If there is a lot of moisture, you'll want to think about a vapor barrier. Paint is the worst option because it will...