removing paint from concrete block wall

I need to remove some paint from a concrete block wall, before waterproofing it. I have a drill that uses bits with 1/4? hex shank. So far I've tried a 4" brass wire wheel and a small brass wire cup. The wire cup doesn't work at all. The wire wheel gets off a lot of the paint, but not all of it. The problem is the roughness of the concrete block surface. The wire wheel does fine at removing the paint from the mortar between blocks. I can get the paint off fine by hand with a tiny wire brush I have, if I really bear down. But I have about 100 sq feet of wall to do, and that would be way too much work. I'm sure sandblasting would get the paint off, but I've never sandblasted anything and I don't know anything about it. I don't know if you can rent a small sandblaster. There's a ceramic tile floor, a wood staircase and a painted closet near that area that would have to be protected. Sandblasting would make a big mess. Is there some kind of wire brush that would work better than the ones I've tried?
thanks Laura
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Graven Water wrote:

Is this wall below grade (ie - a basement wall) ?

Depending on how big this wall is, using a drill with a wire brush can be really labor intensive.
And you can mess up the grouting beteen the blocks if you're not careful.

Ok, so what I'm getting now is that you're working on the *INSIDE* or interior face of this block wall.
I've never had to deal with a water problem for a block wall, but it would be my guess that you can't fix such water problems from the inside. You have to make the wall waterproof from the outside. And I'm thinking this is a basement wall.

I think you're wasting your time.
You don't waterproof the interior side of walls.
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So far a wire brush drill bit is the best idea, and it's not too much work. Does anyone know what would be the best drill bit for removing paint from a concrete block wall? The drill bits I've tried have crimped brass bristles and they haven't worked very well. So I'm wondering whether a crimped carbon steel wire wheel would work better, or perhaps a knotted steel wire wheel. Or maybe some method other than a drill bit. That's the sort of thing I'm interested in hearing about, not other stuff. Laura
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Graven Water wrote:

Why are you trying to apply waterproofing to the interior side of a basement block wall?
You still haven't answered that question.

We're only trying to help you.
You will never stop leaks in a concrete block wall from the inside.
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On Wed, 7 Dec 2011 09:50:15 -0500 (EST), snipped-for-privacy@grex.org (Graven Water) wrote:

A 'bit' is the drilling tool that goes into your drill. [it was easier to distinguish when we used braces with our bits] I think the right term would be 'attachment'.
I've had pretty good luck with Roto Stripper types of tools. Even more dangerous than a wire brush-- and will eat soft spots in your block or mortar, but quicker than a wire brush-- especially on thick paint. (Amazon.com product link shortened)
You will still want an assortment of wire brushes for getting into corners or crevices--- And a full face shield is a good idea with all of those tools.
Jim
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Jim Elbrecht wrote:

Robert Macy wrote:

Your efforts at informing this person are wasted - because of the underlying reason why he/she wants to remove this paint...
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Thanks, picked up on that, but gave me an 'excuse' to share the debacle with others.
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In typed:

Not necessary to know "why".
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Twayne wrote:

For the enlightened and creative thinkers among us - yes it is.
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On 12/7/2011 9:50 AM, Graven Water wrote:

You will not get the paint off concrete block with a power brush. Pressure washing is only way I can even consider, and the paint would have to be loose. Waterproofing INTERIOR wall? Why, in the world?
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On Dec 6, 6:43am, snipped-for-privacy@grex.org (Graven Water) wrote:

I do NOT recommend sandblasting.
From experience at removing years, and years, of paint on an older home. Rented a BIG sandblaster, got 10 bags of small grain sand blasting sand. Power up, loud noise, and sand goes EVERYWHERE! luckily didn't care about the floor. The paint was so hard even the blasting did almost nothing, took a great deal of time to develop the skill to remove the paint, but not much of the wood underneath, nor much of the plaster/lathe at the side of the wood. Sandblasting was so brutal and the paint so hard that sitting on one spot, nothing would happen and then suddenly the sand would chew right down through the wood! After NEVER getting what I wanted, I gave up and simply 'textured' the wood as the sand blasting ate down into the soft bits, leaving ridges of harder growth riings. Stained the bare, textured boards. The final result was an exceptionally interesting pattern of texture, 1/8 to 1/4 inch deep into the wood. But, work was dusty, irritating, hard work to do taking several days, and hurt the ears even with ear plugs. Grit showed up for years, and years, and years. Fifteen years later, when repairing a door latch, dumped around 1/4 cup of sand out of the door before could continue.
No, I don't recommend sandblasting.
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On 12/7/2011 8:41 AM, Robert Macy wrote:

what about a citrus based chemical paint stripper?
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wet basements are very common.
its ultimately impossible to seal water out. even if you seal the walls the water can and will come up thru the floor.
my moms house had a wet basement, I spent 8 grand on new downspout drains to daylight near curb, resloped entire yard, exterior french drain, new sidewalks and steps.
the water stopped for awhile then came up thru basement floor.
I gave up and spent 3500 bucks for interior french drain which finally ended the problem.....
you cant seal water out, the drlock paint will actually bubble.....
drylock paint of any brand is just a grand waste of money and time
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It depends on how much you paid for the concrete foundation and slab when it was poured -- typical residential grade concrete yes, leaks like a bastard... If you pay a little more for a higher psi rated concrete mix, you don't have that problem...
~~ Evan
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concrete can crack, and water leaks at cracks... give any basement enough time and leaks can and will occur.....
redirect water away from basement is only sure method
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I suggest* apply a thin coat of off-the-shelf paint stripper using an old brush, (wear gloves, glasses and long sleeves) wait 30 mins or so then waterblast. [I'm imagining an external wall obviously...]
If there is much residual, wait a couple weeks (provided weather is dry and warm) and then get a professional to sandblast with fine grit. Voila. Bare breeze blocks.
Will NOT stop your water problem. This is cosmetic only.
*I have NOT tried this, but have extensive painting and waterblasting experience.
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