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Genhawk21 10-09-2010 07:45 PM

Moisture in block walls near window?
I am trying to figure out what is going on with this house, hoping someone here can help me.

The house is block, single thickness, built in the 50s. The exterior is stucco, the interior is some kind of parging with no backer (applied directly to block). The windows were replaced about 3 years ago, but this problem predates the new windows because there's a lot of built up patch material in the problem areas.

Basically moisture is getting inside the block somehow. There are through and through cracks in the block, and the interior surface is bubbling. This is all happening fairly slowly. What I can't figure out is how the water is getting into the walls.

Below are some images of the roof, the roof edge directly above, the window corners, and the interior wall.


stuart45 10-10-2010 05:03 AM

There looks to be quite a few cracks in the stucco which would allow water in. Cement renders tend to trap moisture in the walls. This is quite a common problem with them when they crack, especially on solid masonry walls. Lime renders allow the walls to breathe.
Have a read of this

Genhawk21 10-10-2010 01:00 PM

Thank you for the link, that was very informative. Let me see if I'm understanding it right. It sounds like the best solution is to replace either the interior or exterior wall coating (or both) with a more water permeable coating? And perhaps to remove the lowest few inches of stucco on the outside?

If I re-stuccoed, would the existing layer(s) have to be removed, or could I go over the top of what's there with a new layer of a lime render?

Sorry, I don't know much about masonry... :huh:

stuart45 10-11-2010 04:27 AM


Originally Posted by Genhawk21 (Post 514452)

If I re-stuccoed, would the existing layer(s) have to be removed, or could I go over the top of what's there with a new layer of a lime render?

Sorry, I don't know much about masonry... :huh:

You would need to remove the existing stucco before applying the new.
The other way would be to repair the cracks which may be quicker, although the stucco might have blown away from the wall and need replacing anyway.
What sort of climate do you have? I would guess from the flat roofs and shallow pitched ones that it is somewhere like Southern California.

Genhawk21 10-11-2010 02:44 PM

It's in New Mexico, which is overall drier than SoCal. When it does rain or snow, it tends to be heavy, but doesn't last long.

It sounds like for now I should patch, until I can afford to tear off and re-do.

Thanks a bunch for your help!

forresth 10-11-2010 04:42 PM

from the pictures, it looks like the corner is a pooling area on the outside because of the slope toward the window. I'd bet that is your main problem if I am seeing the picture correctly.

Genhawk21 10-11-2010 05:11 PM

How would you go about fixing it? Chip the stucco back until you have a more negative/smooth slope, then patch and repaint?

It certainly seems possible that is at least part of the problem.

forresth 10-11-2010 05:53 PM

I'd probably do more than just chip stucco. I'd keep going untill I got at least a 30degree down slope if it were me.

you might be able to mound in some concrete there after the stucco is all gone, then re-aply.

If I were to guess at the root cause of all this, I'd say poor instalation of the replacement windows.

Genhawk21 10-11-2010 07:05 PM

The original windows were replaced three years ago.

The interior walls were damaged long before, in the same pattern. There are layers of patch inside. So, it can't be just the windows. Right now the walls are barely touched, compared to the damage that was there before.

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