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Community and Q&A

Cleaning a Cement Floor to Prep for Foam Insulation Installation

Hammer 🔨 | Posted in General Questions on

Hi hope everyone is doing well. I would like to clean my garage and basement cement floors. For the basement I’m cleaning it before putting down foam. I removed a chimney so the floor is very dusty. At first I was planning on using a stiff broom with a concrete cleaner and then rinsing it. It seems easier to use something dry like sweeping compound and just sweep up all the dust. Will this be good enough before laying down flooring or do I need to wet the floor?

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  1. GBA Editor
    Kiley Jacques | | #1

    I'll give your question a bump to see if anyone feels otherwise but I don't see any need to clean it to any significant extent--beyond a dry sweeping or shop vac once-over. As was pointed out to me when I asked a colleague about your situation: "In a new build, where the insulation goes in before the concrete, foam is typically put on top of gravel."

  2. Expert Member
    Zephyr7 | | #2

    If you're sealing the concrete first, you'll need a clean surface. I spec a lot of epoxy floors at work, and those need pristine surfaces to adhere properly. If you're just laying down rigid foam panels, I'd just sweep the surface clean and call it good. All you really need to avoid is any big chunks or gravel that will compromise the foam, some sandy grit on the floor shouldn't be an issue.

    Sweeping compound is probably a good idea because you don't want to breathe any masonry dust -- silica dust is a health hazard. If the dust comes up, wear a respirator. You could potentially also wet the surface and then vacuum everything up with a wet vac which would keep the dust down.


  3. DCContrarian | | #3

    There are solutions made just for preparing concrete for painting. I know I got a good one at Home Depot years ago, I can't remember if this was it:

    The good one had a detergent quality that cleaned up all of the dirt and dust and held it in the water and got it off the floor.

    Sweeping compounds are good for corralling loose dirt and dust in the first pass, but they usually have oil or wax in them to hold the dust and can leave a film on the concrete. If you want paint to stick I'd follow a sweeping compound with the clean and etch.

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