Leaking stucco

Ask the pros- July, 2001
By Reggie Bullard


Leaking Stucco
I am writing after visiting your website. I have a problem with my 60 year old stucco home in Minnesota. I have two dormers stuccoed. They leak into the attic space. Each dormer leaks in front of the window. I had a roof replaced recently and the roofer has attempted to seal and reflash around the dormers. We performed a water test and it appears that the stucco is porous enough that water is getting through and leaking into the attic. Is this crazy? I have talked to several contractors about this and few have  heard of stucco leaking. Do I need to have the stucco taken off and replaced with siding? Is there a sealant that I can apply over my stucco which will take care of my water problem? Any suggestions? 

The stucco may be leaking, but I think it's the flashing or the roof. 
Check the picture on the top left: 


Note how the stucco is below the level on the front of the  window. I insisted the roofers extend the flashing to prevent water running in behind the front, damaging the stucco and running into the house. 
The flashing here is the counter flashing. 
The flashing for the slate roof will slide right underneath. 
The reason for this is the stucco has to be done first  on a slate or spanish tile roof, because we can't  walk on the roof. 

On a shingle type roof you should have step  flashing and a counter flashing. Step flashing  will leak. You need a counter flashing to  cover the step flashing. 

Here is your ideal setup: 

Flashing stucco at roof
 We usually patch stucco when someone  replaces the old roof and cuts the wall 
back to run the flashing (and counter  flashing) up the wall and behind the 
stucco. The patch shows but the roof  doesn't leak. 

Check the flashing over the window. Water will  run down the sides of old windows. 

Yes stucco is porous and isn't water proof- but neither are bricks. Bricks are like sponges,  but are still a widely used material. 

You may check over the dormer to make  sure you have plenty of overhang. You 
may want to put a piece of drip edge  between the shingles and the fascia.

You may even check for nail holes on the roof  over the dormer where some one may have hung  Christmas decorations or something. 

We stuccoed a chimney years ago on a new 
addition that leaked. 
I got blamed for the leak, so I went on the roof  and found where some idiot had drive roof about 2 feet away from the chimney. 
I filled the holes and the roof didn't leak any more. 

If you think everything is fine you can paint the stucco  with a masonry paint that will seal it up, but you lose  the natural color and will have to scrape and repaint 
one day, but at least you know the stucco isn't  leaking. 

Hope this helps. 

Thanks for visiting my site.

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