stucco repair: color coat or paint?

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  #1  
Old 06-22-15, 03:38 PM
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stucco repair: color coat or paint?

I am trying to match the color of the repaired patches to the rest of the stucco wall. I have broken out the stucco around the windows for window replacement and proper flashing, and then applied scratch and brown coats, as in the photos (here, the new patches are darker grey vs. lighter grey of the old stucco):

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I am planning to put a colored finish coat on the new patches around the windows and then apply a thin fog coat of the same color to the rest of the wall to hide the repair. I was wondering if one could tell from the photos if the old stucco is painted or color coated? Should I chip a bit off the stucco to see if it is colored through? Because one can't apply new color coats to painted stucco, I want to make sure it's not painted. To me, it looks like it's not, because it looks and feels very differently from the neighbor's painted stucco, which feels a bit like coated with plastic film, not sandy but slippery.

Or is my only option to just paint the entire wall after final coat to the patches around the windows?

Would appreciate any suggestions. Best wishes, h.
 
  #2  
Old 06-22-15, 03:45 PM
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It doesn't appear painted to me. You could brush some denatured alcohol on the stucco and see what it does; if it just evaporates - no latex paint, if a film kind of bubbles up - that would be paint.
 
  #3  
Old 06-22-15, 04:01 PM
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Throw some water on it. If it sheds the water it is paint. If it soaks in and darkens, not paint. Don't worry it will dry.
 
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Old 06-22-15, 05:17 PM
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Thanks marksr and tightcoat!

I threw some water and here are the results: the old stucco darkened a shade, but not as much as the new patch:

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After a few minutes, the old stucco darkened around a thin crack:

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I also rubbed the old stucco with a cloth soaked in alcohol. There was no bubbling, but I noticed that the cloth got colored. After some more rubbing the grey color started coming off (it didn't peel off but rather washed off) and brown color showed up:

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Does it look like color coat of paint?
 
  #5  
Old 06-22-15, 07:55 PM
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i think it looks like paint.
 
  #6  
Old 06-23-15, 01:40 AM
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1 can't apply new color coating to painted stucco ? why not ? we do it all the time how does 1 think condominiums keep their appearance looking presentable ? they paint ! they paint synthetic. they paint traditional hardcoat. they paint over anything

& we help them do it
 
  #7  
Old 06-23-15, 08:07 AM
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By color coat I mean a thin layer of stucco with a powdered pigment in it: finishing stucco mix, which can't be put over old stucco paint.
 
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Old 06-23-15, 11:10 AM
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I painted a lot of stucco when I lived in fla. Painted stucco done right will last 8-10 yrs. Every colored stucco house I saw in fla faded terribly within a few yrs. IMO painted stucco looked a lot better! I know coatings and materials react differently in different climates. I've never visited the west coast much less done any painting there so I don't know how colored stucco holds up in your area.

I've worked with/around stucco guys that would apply a bonding agent to painted block so they could stucco over the paint .... maybe that would be an option.
 
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Old 06-23-15, 11:14 AM
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You can refinish over painted stucco IF you first coat the painted area and in your case it would be a good idea to coat the new work as well with a bonding agent. The standard of the industry is Weld Crete by Larsens' Products. Bonding agent is effective. The new stucco finish will bond to it. BUT the bond is only as good as th bond of the existing paint. If the paint lets loose the new stucco will come with it. It is not advised by Ty company for this purpose but we all do it and get away with it. There are bonded stucco jobs fifty years old that are still sound. It would be a good idea to pressure wash the paint before applying the bonding agent.
 
  #10  
Old 06-27-15, 07:16 PM
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preparing stucco for priming

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Stucco walls have several patches (on the photo) where the old paint has peeled off and, in addition, there are a lot of dark spots of what looks like mold on undamadged paint. I somewhat cleaned the bubbled paint but the mold doesn't come off at all.

Was wondering if I can just ignore the mold and go ahead and prime over them?

Thanks in advance for any comnent!
 
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Old 06-28-15, 05:15 AM
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What did you use to clean it? Bleach should work, be sure to rinse well.
 
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Old 06-28-15, 04:58 PM
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It could be algae, not mold. I had this problem. I tried bleCh it did not work. I think try some trisodiUm phosphAte, get the real stuff, then bleach then some other algecide, maybe some dilute muriatic acid then anything else that seems like it would kill Algae. The problem is that the stuff has grown into the stucco and when it gets wet again it will bloom out again. I honestly don't know if you can get rid of it. But if you just finish over it it will come back. I don't know how soon it will return but it will.
 
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Old 06-29-15, 01:03 PM
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Thanks again, marksr and tightcoat! I cleaned the wall with water and sponge; the water runs down pretty dark with all the dirt and dust.

Is it required for re-painting that I power-wash the painted stucco with a detergent first? Someone has suggested that a good primer can tolerate some dust and power wash is not that important, in fact, it can even damage old stucco and woodwork. The stucco doesn't look dusty, but maybe this is not clean enough for priming? Thanks again for all the feedback.
 
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Old 06-29-15, 02:20 PM
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Paint always adheres best to a clean substrate! If it's just dust it should rinse off but chalk can be a real problem. To remove chalk use TSP [add bleach if needed] and rinse well. A pressure washer makes the job easier/quicker but a water hose will work well. If you can't remove all the chalk, add Flood's EmulsaBond to the 1st coat of latex [paint or primer] The amount to add depends on how severe the chalk is.

Stucco is pretty hard on a sponge, I'd use a brush instead
 
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Old 07-03-15, 03:53 PM
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elastomeric on wood?

Thanks, Marksr! I have cleaned the stucco part of the house with TSP/Chlorox mix -- the black spots are gone, scrubbed off or bleached.

Now I have to clean the painted cedar shingles walls before repainting. The old paint is in great shape: no bubbling or peeling.

Would leftover elastomeric stucco paint be acceptable for repainting cedar shingles? I think it is, because many use oil-based primer when painting cedar shingles first time. Aren't oil-based paints even less moisture-permeable than a thick layer of latex paint?
 

Last edited by harum; 07-03-15 at 04:38 PM.
  #16  
Old 07-03-15, 04:54 PM
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I'm not a chemist so my explanation might not be perfect but the molecules in solvent based coatings are closer together than the molecules in latex coatings. This allows oil base coatings [including primer] to seal better from both stains and moisture. Elastomeric paint is something like a caulk based paint and provides a water resistant seal that way.

As long as the cedar shingles are primed or previously painted and not chalky!! the elastomeric would be ok although a latex stain or house paint would be better.
 
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Old 07-03-15, 05:59 PM
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Thanks, yes, makes perfect sense! I'm just confused when some say that it's okay to use an oil-based primer on cedar shingles. But not okay to use elastomeric as a coat because shingles have to breathe.
 
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Old 07-04-15, 04:57 AM
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Whether or not shingles [or any other material] needs to breath depends mostly on what is behind them. On older homes without vapor barriers it's usually beneficial to use latex only so the siding can breath so moisture that migrates thru the wall isn't overly restricted BUT if no moisture gets behind the shingles, there isn't a big need for them to breathe. Whenever cedar is painted a light color it requires an oil base primer to stop tannin bleed although it is a lesser problem with older/aged cedar.
 
 

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