# Stucco over CMU question



## CJKarl (Nov 21, 2006)

I get a call from a guy about a stucco problem. Here it is.

It's about a 10 year old free standing block garden wall. 6' tall with a stone coping. Customer says he had a few spots, couple feet in diameter cracking and falling off. He had a stucco guy come back in last spring and chip off the loose stuff and re-apply stucco, then paint with some high-end flexible paint.
He also cut out the joints in the coping and it appears, caulked them. The whole repair looks neat and tight...but,
In the spots that he said had the problems, you can now see a slight bulge starting right on the head and bed joints of some of the block. I don't see how water would be getting in there. The repair looks real tight. I don't know if this happened as they were applying the repair (soaking wet joints?) or if it just started a couple weeks ago as the owner stated.
Any of you stucco master know what may be going on here?
No it's not on wire or foam.
I told him he may have to just cover it up with an EFIS type system.


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## CJKarl (Nov 21, 2006)

Nutt'in??


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## Tscarborough (Feb 25, 2006)

The only thing an think of is efflorecence under the repair blistering the coating, but it generally will stop if the water intrusion stops. Sprinkers?


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## concretemasonry (Dec 1, 2006)

Does the coping have a positive drainage, overhang and a drip? Is it the same coping that was there initially and during the first surface failure?

If not the water could just follow the surfaces down and feed moisture into the wall than can destroy a wall surface in many ways depending on the type of climate.


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## bwalley (Jan 7, 2009)

CJKarl said:


> I get a call from a guy about a stucco problem. Here it is.
> 
> It's about a 10 year old free standing block garden wall. 6' tall with a stone coping. Customer says he had a few spots, couple feet in diameter cracking and falling off. He had a stucco guy come back in last spring and chip off the loose stuff and re-apply stucco, then paint with some high-end flexible paint.
> He also cut out the joints in the coping and it appears, caulked them. The whole repair looks neat and tight...but,
> ...


It is wicking water up through the footer, wall footers don't have a vapor barrier in them and they wick up moisture, that is why elastomeric paint on all 3 sides are a bad idea.


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## CJKarl (Nov 21, 2006)

The cap has an 1 1/2" over hang, as I said before, the cap joint repair looks real tight.
Water could be wicking up from the ground, but it was redone in the spring and we haven't had any freezes yet.
Thanks for the good point about the wall being totally sealed. I'll try to get some pictures this week. I told the guy to wait and see what happens. If it's going to get repaired again, waiting isn't going to hurt.


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## bwalley (Jan 7, 2009)

CJKarl said:


> *The cap has an 1 1/2" over hang, as I said before, the cap joint repair looks real tight*.
> Water could be wicking up from the ground, but it was redone in the spring and we haven't had any freezes yet.
> Thanks for the good point about the wall being totally sealed. I'll try to get some pictures this week. I told the guy to wait and see what happens. If it's going to get repaired again, waiting isn't going to hurt.


The water is not coming in from the top of the wall, it is coming in through the footer.

It isn't rocket science, concrete wicks moisture from the ground and when you encapsulate it with elastomeric coatings you get these kinds of problems.

With walls you have more problems with mositure wicking up the wall than coming in through the sides, if you want to keep water from coming in from the top, use elastomeric on the top but not the front and back side of the wall.


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## CJKarl (Nov 21, 2006)

bwalley said:


> The water is not coming in from the top of the wall, it is coming in through the footer.
> 
> It isn't rocket science, concrete wicks moisture from the ground and when you encapsulate it with elastomeric coatings you get these kinds of problems.
> 
> With walls you have more problems with mositure wicking up the wall than coming in through the sides, if you want to keep water from coming in from the top, use elastomeric on the top but not the front and back side of the wall.



Thanks bwalley, so pretty much the guy is fawked? :laughing:
I'll tell him to EFIS it....and let his grand kids worry about replacing the wall.


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## bwalley (Jan 7, 2009)

CJKarl said:


> Thanks bwalley, so pretty much the guy is fawked? :laughing:
> I'll tell him to EFIS it....and let his grand kids worry about replacing the wall.


Not sure if EFIS would fix it or not but if you can get the front and backside of the wall stripped of the elastomeric coating, fix the wall, paint it with a paint that breathes, like a satin or a flat paint, it should be OK, it is not a bad idea to coat the top of the wall and maybe 6"-12" down the front and back from the top with elsatomeric, it will keep water that sits on top of the wall or gets on there by rain from soaking into it.


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## DJ9222 (Apr 28, 2009)

I agree with my fellow masons that the moisture is coming up thru the footing, one solution might be to put french drains on the front and rear to get the water away from the wall, then you might be able to stucco again with no problems.........
Good luck.....


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## Red Adobe (Jul 26, 2008)

I have to wonder if that small of an area had some kind of oil or other uncompatable on the block..... 

I did some plasterin in my 20s and i know EGG will cuase all kinds of hell.

We sprayed all tools with wd40 and sometimes it got on things it wasnt suposed to with new guys who didnt let it dry before loading the hawk

I got a delivery of blocks for a foundation awhile back that had road grime of an oily nature all over the front of the first pallet ( i marked em and made sure the oily side went to the inside )

It may not be an actual water problem is all im thinkin......


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## CJKarl (Nov 21, 2006)

Went back today. I have some pics, but I'm having trouble moving them around. I'll try again. The repairs the stucco guy did last summer are falling apart. It's definitely soaking wet behind the stucco. 
One side of the wall is T&G cedar. Very tight and nicely done. Possibly "some" water could be coming in through that side. The stones capping the wall still look very tight. The joints were raked and replaced with caulk. Then the stones were sealed. We're getting a carpenter in next week to pull some trim off the outside of the wall and do a little exploration.
The thought now is to pull the caps, repair the stucco, flash with copper leaving drip edges exposed, then replace the cap stones. There are numerous other walls built at the same time with the same materials and have not had a problem in 10 years.


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## CJKarl (Nov 21, 2006)

pic


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## CJKarl (Nov 21, 2006)

cap


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## CJKarl (Nov 21, 2006)

stucco


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## CJKarl (Nov 21, 2006)

more stucco


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## CJKarl (Nov 21, 2006)

Inside of wall


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## CJKarl (Nov 21, 2006)

outside of wall


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## CJKarl (Nov 21, 2006)

Excavated base of wall. Dark spot on right is soaking wet. Outside of the wall (wood side) was power washed about an hour before I got there. A clue. :thumbsup:


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## CJKarl (Nov 21, 2006)

Bed joint is caulked and tight.


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## Tscarborough (Feb 25, 2006)

That is a nice looking wood wall, but the chair rail is flat. I don't feel good about the wood wall. Did they waterproof the CMU behind it? Are all the pop-offs below the chair rail height?


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## CJKarl (Nov 21, 2006)

I don't know whats behind the wood. I know the guy that did the carpentry on the job and he is an excellent craftsman....but that doesn't rule out the wood as a problem. We are going to pull some of that off next week and see whats behind it. It may be as simple as removing the wood, sealing the crap out of the block and putting the wood back on.


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## CJKarl (Nov 21, 2006)

Most of the damage is above that "chair rail" trim.


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## superseal (Feb 4, 2009)

I do a lot of these walls and use Thorolastic breathable coatings (elastomeric) with pretty good success. However, proper application applies; pin hole tight thickness, etc... copings need to be perfect and rising damp "is" a big issue. 

Design is the ultimate culprit - No pan, through wall flashing under coping, weeps, no damp course flash and how bout footer drains :no: 

Generally speaking, unpainted stucco breathes best; Elastomerics will lower the perm rating and prevent drying when saturation occurs - that's why these walls are always soaked, at least spot soaked.

Since the wall is now coated, you might focus on drainage and drilling weeps. I would also double check the coping joinery and bed joint - these are critical. A relief drip cut on the copings would be good too :thumbsup:

Patch all loose or missing stucco using Planitop x or equiv. and allow to throughly dry before re-coating. Think of it as job security - you'll probably be back every few years :hammer:


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## stuart45 (Oct 7, 2009)

Iv'e got the same problem in my lounge. As it's an old cottage with solid stone walls built without a damp proof course it's got rising damp. The walls were replastered in the past with sand/cement instead of lime which lets them breathe,the render has blown in places. The rising damp also brings up hygroscopic salts which attract moisture and make it worse.


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