Sealing a semi-painted concrete floor?

Discussion in 'Concrete Flooring' started by GrindingInAustin, Jan 12, 2020.

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  1. Jan 12, 2020 #1

    GrindingInAustin

    GrindingInAustin

    GrindingInAustin

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    Hello and thank you for any help you all can give us.

    My wife and have taken up some laminate "wood" planks in our closet to investigate the possibility of going with a concrete floor. After removing the planks and rolling back the blue plastic barrier the slab looks to be painted with a white paint, perhaps a moisture barrier / primer. Looks deliberately painted and not just over spray from the walls.

    I easily scraped some up with a water based stripper if that lends any insight to what it might be.

    So just for grins I took out the big grinder and a 50 grit diamond pad and sanded a larger portion of the painted floor to see what it would do. It made the floor very smooth and removed about 60% - %70 of the paint.

    We stood back after wiping it with a wet cloth and thought the mottled / distressed look might be very attractive.

    My question is does anyone see any potential problems with sealing it like that? Sealer adhesion issues?

    I have had concrete floors in the past and am familiar with regular waxing etc to keep them looking good.

    Please see photo, thanks!
    [​IMG]
     
  2. Jan 12, 2020 #2

    havasu

    havasu

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    Looks like that is just overspray from when they painted the walls and ceiling before the carpeting went in. How would you deal with those glue lines from the rubber padding?
     
  3. Jan 12, 2020 #3

    GrindingInAustin

    GrindingInAustin

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    Thanks havasu, I think your right about the over spray as the paint is much thinner towards the middle of the floor. I'm not sure about the glue, I touched it a bit harder with the diamond pad and it looks to be coming off, I could try a little acetone maybe?
     
  4. Jan 13, 2020 #4

    GrindingInAustin

    GrindingInAustin

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    floor after sanding (2).jpg I decided to run my 50 grit pad a little more on the rest of the closet floor to see get a better idea of what the paint will do and I think we'll just take it all down to bare concrete. We are fortunate (so far) to have what looks to be a nice slab.

    A little off topic but I hoped maybe havasu could advise:
    The 50 grit pad get things pretty smooth, I wonder how high of a grit you typically go up to for a residential floor?
    We're not looking for a mirror polish but want furniture to slide easily :)

    Thanks!
    Here is a updated photo after going over it with a wet mop:
     
    Last edited: Jan 13, 2020
  5. Jan 13, 2020 #5

    havasu

    havasu

    havasu

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    Honestly, I've seen this done a few times, and they look awesome. The problem with your floor is the small nail holes along your entire perimeter from the old tack strip, which held down your carpeting. You can fill them in, but will always stand out. What is your remedy there?
     
  6. Jan 13, 2020 #6

    GrindingInAustin

    GrindingInAustin

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    In a previous home I used mapei concrete patch to fill in holes and it worked very well and sanded smooth. You are right though, the patches are somewhat visible depending on the tone of the adjacent concrete.
     
  7. Jan 13, 2020 #7

    havasu

    havasu

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    How about a skim coat of self leveling compound around the entire floor, give a light sand, stain and coat with a poly coating?
     
  8. Jan 13, 2020 #8

    GrindingInAustin

    GrindingInAustin

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    That would give the best results but I have an entire house to do and that might be too much work for us I think. I'll know more when more flooring is taken up and the full slab condition is revealed.
    I hate tack strips! :)

    Do you have experience with grit levels that these types of floors are brought up to?
     
  9. Jan 13, 2020 #9

    havasu

    havasu

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    A smaller grit will allow a good binding surface, provided you are coating with a poly type coating. If left raw, 200 grit would be minimum.
     
  10. Jan 13, 2020 #10

    GrindingInAustin

    GrindingInAustin

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    Thanks, I'll try to update this thread periodically as questions come up and our progress continues. It might help someone else also.
     
  11. Jan 13, 2020 #11

    havasu

    havasu

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    Keep in mind if you are dealing with a full slab flooring, expose the entire floor to see if you have a stress fracture somewhere in the floor. I found a huge fracture running down my hallway, which made me forget about a concrete floor treatment, and opted to run wall to wall porcelain plank tile instead, using "Redgard" 4' wide near the crack to allow for expansion/contraction.
     
  12. Jan 20, 2020 at 2:07 AM #12

    GrindingInAustin

    GrindingInAustin

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    I really like the look of those porcelain planks. Redguard is interesting stuff, I would like to learn more about it.
    We have now exposed the entire master bedroom floor and so far the slab is looking good, flat and no cracks. I have decided to dry polish with my 7" inch variable speed grinder using grits 50, 100, 200, 400, then apply a lithium silicate densifyer, then 800 grit and see what we get before going higher.
    I have a great dust shroud attachment for my grinder that attaches to the shop vac for nearly dust free sanding, very cool.
    I'll be back with pictures soon.
     
  13. Jan 20, 2020 at 2:17 AM #13

    havasu

    havasu

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    Please. We love pics!
     

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