# Repairing surface delamination of exterior stucco wall



## miamicuse (Nov 13, 2011)

I have two spots on the exterior block walls with some surface stucco cracks. After breaking and scraping off everything loose I end up with a blueish cement surface below the stucco.























I am not 100% sure what I am looking at. I don't think this is the "raw" concrete block surface, so most likely what broke off is the finished coat and what I am looking at is the base coat of stucco? But why would it be blue? Or am I looking at a house with smooth stucco once upon a time painted blue, then later on someone applied an additional layer of textured stucco with olive green paint? The layer that I scrapped off is about 1/8" thick. The house was built in south Florida in 1941.


If I want to patch this up should I apply bonding agent to this area and just trowel on a thin layer of type S stucco then prime/paint over? Or should I use a wire wheel to remove the blue color stuff whatever that is first?


If I need some bonding agent is the blue bonding agent by Lanco good for this application?


Thanks in advance!


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## Windows on Wash (Aug 30, 2011)

Whats the wall construction? Appears to be a poured wall the the white staining is likely efflorescence which was contributory to the top coat failure. 

You have to get the moisture out of that wall or it will continue to push off the top layer regardless of bonding agent.


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## ClarenceBauer (Mar 4, 2005)

I have some questions.
1 is the Blue color material soft or rubbery to the touch?
2 in photo # 2 it appears that there is a blue tint on the brick surface?
3 If you wet it will it get tackey?
From the looks based on the photo's it appears that a bonding agent was used & if the bonding agent was re-emulsion able it would fail due to the presents of moisture. The Stucco is in contact with the Brick walkway.
Also Windows on Wash. is correct efforesence will cause delamination between the two surfaces.
If & when you patch do not use type "S" mortar use a type "N".


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## miamicuse (Nov 13, 2011)

ClarenceBauer said:


> I have some questions.
> 1 is the Blue color material soft or rubbery to the touch?
> 2 in photo # 2 it appears that there is a blue tint on the brick surface?
> 3 If you wet it will it get tackey?
> ...



Hi Clarence,


#1 - the blue color material is hard. Not soft or rubbery.
#2 - I think it's just the lighting. There are some darker mildew spots on the bricks from all the rain that's in south Florida.
#3 - if I blast that surface with a garden hose it does not get tacky.


Here is a picture if I take two steps back. Here you can see this is part of an outdoor bar/kitchen, but it's the same construction as the actual block wall house.












On the other side of this bar is a recess under the sink. Here you can see clearly it's 16X8 concrete blocks and someone put a lousy looking incomplete coat of whatever on it.


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## mark sr (Jun 13, 2017)

I can't help but think the blue is some faded paint from long ago which would make me believe the green painted stucco isn't original to the house.


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## ClarenceBauer (Mar 4, 2005)

I would agree with MARK SR than it is a paint coating being it is hard & does not soften when wet.
The cause is as WINDOWS ON WASH stated moisture causing effervescence behind the thin coating of Stucco.
You will need to stop the water from entering from the counter top area & from the ground level.


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