Moisture coming through Stucco Wall

Posted by C. Bailey on August 25, 2005, 1:23 am

I just bought a house. The house is 3 years old. It has a stucco exterior.
For the last day, it has been raining with a strong wind (we haven't had a
lot of rain before this). The rain is hitting the walls (normally the eve
protects the walls somewhat). I now have a constant drip from the top of
one of my windows in the basement (walk out basement - drip is about 8 or 9
feet above grade). I pulled the insulation and discovered the plywood is
saturated with water. I inspected the stucco exterior and it appears
normal. I pulled insulation above a couple other windows. The plywood is
slightly damper, but not dry like it should be. Any thoughts as to what the
problem might be?
Is stucco a water proof coating, or is there supposed to be tar paper behind
it?
Chris

Posted by Sacramento Dave on August 25, 2005, 2:07 am

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exterior.
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the
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behind
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this same problem how I fixed it was to caulk were the stucco meet the
overhang, then for added protection I put a 1X2 as trim I also caulked
that.You might try spraying the area with a hose. See if that increases the
drip. There should be tar paper behind stucco It's part of the lath.

Posted by Rick on August 25, 2005, 4:13 am

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haven't had a
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the eve
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top of
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about 8 or
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plywood is
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appears
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plywood is
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to what
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paper
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If you can find the July 2005 issue of the Journal of Light
Construction, there's a good article called "Why Stucco Walls Got Wet"
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I had
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the
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caulked
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increases the
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Posted by Travis Jordan on August 25, 2005, 11:41 am

C. Bailey wrote:
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Masonry of all types is not impervious to water. Stucco should be
applied to a wall that has first been prepared by hanging a weather
barrier (felt or tyvek or equivalent) overlaid with wire lath before the
stucco is applied. Even so, the finished stucco is still slightly
permeable.
Paint and elastomeric coatings prevent penetration of water on masonry
surfaces. Many stucco homes are painted with latex acrylic paints, and
are therefore more waterproof. However, during last year's hurricane
season here in Florida it turned out that many newer homes with only one
or two layers of paint still leaked.
Some homes are built with synthetic stucco (dryvit) and moisture
penetration of this material is common.

Posted by Norminn on August 25, 2005, 7:28 pm

Travis Jordan wrote:
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The news about wind-driven rain permeating concrete block/stucco was
really interesting. That is what we have. Wind hard enough to drive
water through cb/stucco would also, probably, find all the little
wiggly, unfilled gaps and joints between members. Curious as to the
windspeed when OP's house got wet. A benefit of our hurricane shutters
is probably that we are a lot less likely to get water in closed
windows/patio sliders. Tide surges and flying roofs are enough to
handle :o) We had a 5'x15' foot skylight take flight last year, but a
sturdy palm caught it :o)
Wind here can easily enter roof vents, soffit vents, etc. Our old condo
has lotsa paint, so that is a surprising benefit.

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