Painted concrete basement floor keeps dusting and crumbling
Concrete floors dust and crumble when the surface is inadequately prepared before painting or damaged during renovations. This breakdown lets dust push through the failing paint and prevents you from maintaining a clean, sealed surface.
What the numbers show
Counted from the threads quoted below. How we count
- The most recent one is from October 2026.
- This comes up 50.8× more often in r/Flooring than across the site as a whole.
What people tried
Every workaround mentioned in the threads below. We haven’t tested any of them — and nobody here is claiming they worked.
Found another way around this?
Share your steps and trade-offs so fellow engineers don't have to reinvent the wheel. No account required.
- 1Filling the center under the level repeatedly with leveling compoundDid this help you?
- 2Extend levelers with pea gravelDid this help you?
- 3Patch the big hole with cheaper concrete then level over itDid this help you?
- 4Grinding down expansion seams using an angle grinder wheel, diamond disc, and dust shroudDid this help you?
- 5Using a chisel and hammer to take down large seamsDid this help you?
- 6Renting a 9-inch angle grinder or a 10-inch push-behind concrete grinderDid this help you?
- 7Switching to alternative flooring types like metallic epoxyDid this help you?
- 8Laying a 6-mil polyurethane vapor barrier as a moisture barrierDid this help you?
- 9renting a heavy floor sander to scuff up the surface before repaintingDid this help you?
- 10scraping loose material and painting directly over the existing surface without sandingDid this help you?
- 11installing commercial carpet tilesDid this help you?
In their words
Unedited, grouped by where they were said, most upvoted first within each place, each linked to the thread it came from.
“The issue I'm running into is the high spots on the concrete expension seams.”source ↗
“Regardless of my best efforts, it also made a mess blowing concrete dust everywhere.”source ↗
“Unfortunately, there's still a 5/8" height difference at 6ft out from the seam's ridge.”source ↗
“I'm at a point where I need to commit to either taking the subfloor out and fixing the issue, or move on with it as is.”source ↗
“I have a 700 square foot basement. It was epoxied at some point but is now full of chips and stains. I’m thinking about using a floor sander to scuff it up, then priming it and painting everything a flat color using concrete floor paint. I’m very much an entry level DIY-er. Am I signing myself up for a head ache to do this?”source ↗
“Struggling with trying to flatten the concrete. Theres a big dip in my subfloor, with a 5/16th gap under my 6.5ft level. Do i need to keep filling the center under my level?”source ↗
“Obviously it's a deeper hole over more concrete foundation, so I'm unsure what the best self levelling or other compound is going to be suitable to fill this and other gaps to be found elsewhere later.”source ↗
“Confirming you can see brush stokes in it, so aligned that it might just be painted over. Guess I’m moreso curious what my options are at this point.”source ↗