localized water stain under the windows on stucco

[Peter Louis]

Sometimes found this kind of water stain under the window cornor but the other windows on the same postion are fine. Also this kind of stain at a certain spot on stucco sometimes. The interior is ok no moisture damage. Is this the cause that cracks on the stain location are serious, which the water gets behind siding & is dry slower than other area?

Thank you

[Steven Turetsky]

Miter joints are a very common place for windows to leak (regardless of the type cladding).

[John Kogel]

Hello Peter. Big wet stain on a wall. First check for the obvious. Is there a low spot in the gutter there, that spills water onto the lower roof?

Yes, the window appears to be leaking at the corner, but the overhanging roof should normally keep the window and wall relatively dry. An overflowing gutter may be causing all that water to hit the window.

[Rick Cantrell]

I agree with John
In fact close up of 2nd photo seems to show water on soffit at gutter over window.

[Peter Louis]

Thank you guys. I watched gutter which was not bad. I am just wondering it is the sign to paint & service the stucco even without the accutual water intrusion.

[Steven Turetsky]

Thank you guys. I watched gutter which was not bad. I am just wondering it is the sign to paint & service the stucco even without the accutual water intrusion.

Perhaps it is time to test the stucco to determine if there is water intrusion.

[Tom Rees]

Peter, Is that an exhaust fan vent on roof below?

[Peter Louis]

Peter, Is that an exhaust fan vent on roof below?


Yes, it is. Any significant effects?

[Tom Rees]

I only say that Peter because things aren't always as they seem and sometimes we overlook the obvious.

[Dominiclp]

a few thoughts - the stucco cracks may be in part the result of water infiltrating the stucco and deteriorating the mechanical attachment and or the lath. the other part of that is that the stucco does not have proper length to width ratio and or panels. I see three cracks under this window - if this is the only window with cracks than I would assume that the cracks resulted from the water. however the cracks are more likely the result of the length width ratio in the section of stucco under the window and over the roof. the window perimeter does not look like it has a sealant joint so there may be variation in the tightness of the stucco window interface at this window that is unique compared to the other windows. finally, a window defect like a poorly sealed seem at the sill jamb or materials failure would likely be typical of all the windows. considering these points the potential contribution from a gutter problem above appears to be as likely. you seamed to indicate that you observed the contribution of the gutter, is this true?

[Thomas McKay]

The left side of the window appears cloudy indicating a failed glazing seal; defective miter joint, poor sealing of the window flashing all can contribute to rain water getting behind the stucco in a frame home. This condition is very common in my market especially where poor quality windows are used. Repair can be expensive, recommend it be looked at by a qualified stucco contractor.

[Peter Louis]

The left side of the window appears cloudy indicating a failed glazing seal; ...

Thomas: there is no failed window seal & cloudy. That may be the poor shot.


the other part of that is that the stucco does not have proper length to width ratio and or panels.

Dominic: Can you explain this? I want to know. Thanks.



I only say that Peter because things aren't always as they seem and sometimes we overlook the obvious.

What Tom said could be a reason. But does the vented steam have such tremendous effect?