cleaning cement blocks


  #1  
Old 07-26-02, 09:38 AM
harold.pohl
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cleaning cement blocks

I have a patio made of cement blocks and it has become dark and discolored by moss, fungus, mold, grime, etc., etc. Does anyone know a way to clean it so it looks presentable again? I've tried chemical preparations and they help - a little. I'm looking for a dramatic improvement.

Thanks for any suggestions.

Harold Pohl
 
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Old 07-27-02, 07:02 PM
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cleaning cement blocks

harold.pohl,

I noticed this hasn't been answered by anyone but I am not experienced enough in this area. Since you have tried chemicals and were not satisfied with the results, have you talked to any Deck and Patio firms that may give more insight to this? I assume you don't want to replace them due to cost but if they are honest, they may provide some great advice and won't try and sell you something.

Is sandblasting an option? I assume that if you used chemicals, that is if the blocks were painted, the paint came off, right?

What exactly is the improvement that you desire? Ask around where you live, maybe someone can come over and look at what you have. It's worth a shot!

Good Luck!
 
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Old 07-28-02, 01:44 AM
harold.pohl
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cleaning concrete blocks

Doug,

Thanks for your response to my question.

The improvement I am looking for is to clean and restore something of the original tone and color to the concrete patio blocks, which have become very dark and in some spots mossy. I am trying to avoid the cost of redoing the whole thing, but that may be the right solution. I haven't had anyone who constructs patios look at it yet and am trying to find out if I can do anything myself before going in that direction. Sandblasting did occur to me, but I have never done it and so don't know what I could expect the resulkt to be. It sounds to me like a promising possibility.

Thanks for helping.

Harold Pohl
 
  #4  
Old 07-28-02, 04:19 AM
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Harold,

You might be surprised what a good pressure washing will clean.

fred
 
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Old 07-28-02, 05:57 AM
harold.pohl
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cleaning concrete blocks

Fred,

Thanks for your reply to my question. I hadn't thought that pressure washing would be strong enough to clean off the stuff on my patio concrete blocks, but will look into it. Is some kind of cleaning substance used with pressure washing or is it just the force of water under pressure that does the cleaning?

Harold Pohl
 
  #6  
Old 07-28-02, 07:55 AM
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Harold,

Similar to a deck, if you pre-spray(garden pump up) with a bleach, it will kill mildew and some algae. I use an oxygenated bleach(Wolmans Deck Brightener) as it is not harmful to surrounding grass and plants. But you are right, it's the pressure which removes most of the dirt and grime. My brick walk on the North side of my house gets covered with algae. I can get it quite clean with my 11hp, 3500 psi pressure washer. If you rent a PW, get atleast a 2500 psi unit. And, be sure to wear eye protection.

fred
Deck-Kleen Powerwashing
 
  #7  
Old 07-28-02, 10:42 AM
harold.pohl
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fewalt,

Thanks very much for the info on power spray cleaning. These are just the tips I needed to encourage me to give it a try on my patio cement blocks. Thanks especially for the safety tip.

I enjoyed your little animation also.

Harold Pohl
 
 

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