Bricks, Masonry, Asphalt and Concrete - Bleaching Old Concrete
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rckowal
07-25-03, 07:25 AM
Had a new driveway installed as well as some adjacent slabs in the sidewalk and service walk. Now, of course, there is a patch work look since the color of new concrete is near white while the old slabs are grey. Is there a way to bleach the grey colored slabs to minimize this appearance? Your assistance will be much appreciated.
chfite
07-25-03, 09:01 AM
This may help.
http://www.homestore.com/HomeGarden/HomeImprovement/HowTos/HowTos/CRHO_CleaningConcrete.asp?poe=homestore
http://www.superdeck.com/masonsselect/6500spec.htm
Hope it does.
http://www.homestore.com/HomeGarden/HomeImprovement/HowTos/HowTos/CRHO_CleaningConcrete.asp?poe=homestore
http://www.superdeck.com/masonsselect/6500spec.htm
Hope it does.
rckowal
07-26-03, 07:59 AM
Thanks for the reply Chris, it's appreciated. I've looked at the web sites you suggested & they contain some helpful information. Unfortunately, some of the product brands shown are not available in this area - S.S. Michigan - but I'm sure there are some equivelents.
fewalt
07-26-03, 10:06 AM
A light bleach solution and pressure washing will lighten the old concrete considerably.
fred
fred
rckowal
07-26-03, 04:53 PM
Thanks for the tip Fred. I'll test that on a bit of concrete that's not usually visible to see how it works. Do you have any idea if Oxyclean (oxygen bleach) works as well as chlorine bleach? If so, I think it it would be some what safer to work with.
Local contractors supply house recommended "simple Wash" by Biowash. It contains two mild acids - phosphoric & sulfonic acid. It's strong but doesn't etch or pit like muriatic acid.
Best regards.
Local contractors supply house recommended "simple Wash" by Biowash. It contains two mild acids - phosphoric & sulfonic acid. It's strong but doesn't etch or pit like muriatic acid.
Best regards.
fewalt
07-26-03, 05:37 PM
rckowal,
The OxyClean will kill algae and mildew and should work fine.
Biowash is a good product, but like you mentioned, the Oxy is much safer and harmless to plants. Give it a try first.
fred
The OxyClean will kill algae and mildew and should work fine.
Biowash is a good product, but like you mentioned, the Oxy is much safer and harmless to plants. Give it a try first.
fred
rckowal
07-27-03, 07:30 PM
Tried some tests on dingy concrete & here are the results.
!. One part chlorine/two parts water gave the best results.
2. One part Biowash brand "Simple Wash"/three parts water was very nearly the same as "1." above.
Surfaces being cleaned & surrounding vegetation were pre-wetted with water to protect plant life and to minimize absorption of cleaner into concrete.
Both cleaners were applied by spray, allowed to set for 5 minutes then scrubbed with coarse floor brush. Allowed to set another 5 minutes & rinsed with water.
There was very noticeable lightening of the grey concrete but it wasn't near as white as the newly poured slabs.
!. One part chlorine/two parts water gave the best results.
2. One part Biowash brand "Simple Wash"/three parts water was very nearly the same as "1." above.
Surfaces being cleaned & surrounding vegetation were pre-wetted with water to protect plant life and to minimize absorption of cleaner into concrete.
Both cleaners were applied by spray, allowed to set for 5 minutes then scrubbed with coarse floor brush. Allowed to set another 5 minutes & rinsed with water.
There was very noticeable lightening of the grey concrete but it wasn't near as white as the newly poured slabs.