About ten years ago I used sani-tred to waterproof my basement walls they were new construction bare cinder block at the time. I have had some water filtration over the years not a lot but enough to leave a puddle in the corners after very heavy rain. I also have mold trapped between the layers of the paint. I tried to remove the paint which is a liquid polyurethane with power washer 35000 psi and chemical stripper with very poor results. Was thinking maybe sandblasting or dry ice would work? I would like to get the wall bare again and try to seal any leaks with hydraulic cement. Any suggestions would be greatly appreciated.

  • 2
    I'm pretty sure you'll need to use some sort of mechanical process to remove it; once dried, polyurethane is really tough to dissolve. Feb 24, 2016 at 2:45
  • This guy used a grinder: youtu.be/Z824geZffQ4
    – RetiredATC
    Jul 30, 2022 at 18:21
  • Wow... I just realized the OP has a 35 thousand PSI pressure washer. That's a lethal weapon!
    – FreeMan
    Mar 28 at 15:49

1 Answer 1


I would try a Muriatic acid and water solution. I know the Acid will etch the Block just not sure how well it will remove the sani-tred. I would start with a 10% acid solution and work up from there. Usually I do this to floors prior to painting. If I need to make the surface rough for better bond for tile it works also. I have used mixtures up to 30% depending on how aggressive I want to etch the cement. You will need fresh air in a basement as the fumes can get quite strong. Remember to always add acid to water and use rubber gloves to protect your hands. All pool supply stores will carry Muriatic acid and most home improvement carry it. It is not that expensive for a gallon to give it a try.

  • 2
    I doubt acid will touch polyurethane. You probably would have to use an extremely aggressive (and probably toxic) organic solvent to dissolve it now that it's dried. Feb 24, 2016 at 2:44
  • I bet the acid would loosen the polyurethane's hold on the block though. Seems like a long, painstaking process at best, with a lot of damage to block before even most of it was removed. Just my thoughts, haven't tried it. What did you end up doing @joe ?
    – rdtsc
    Sep 1, 2018 at 21:38

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