I have two windows on one side of my house, with one directly above the other as pictured below. During rain storms, water rolls directly off the top one on to the bottom one. Water gets into the house via the bottom window this way. I’ve checked the caulking above the bottom, which was initially in poor condition, and recaulked around it. Water still came in the house afterwards.

I think the water is coming in from the bottom of the window sill, since the paint on the wall below the window sill is blistered and there’s a puddle on the floor. Additionally, I don’t think it’s the gutter because the top window has no such problems. I'd like to add additional flashing above the bottom window but I’m just not sure how to go about doing it.

The siding is stucco, so my only idea would be to install something like [this] 1 over the bottom window with screws for driving into concrete. Would that work? What other methods would? Thanks

the windows from the outside

bottom window from the inside

  • 2
    I've rotated your images for you. However, your link to [this] is a link to googleadservices and isn't pulling through properly. Remember that if you get a link from Google's search results page, you get loads of tracking info that G uses to get you there. If you actually click the link & wait for it to open in the browser, you can get the actual link from the address bar. <shameless promotion: DuckDuckGo's search engine will give you a real link directly from the search results and they don't track searches at all>
    – FreeMan
    Commented Sep 8, 2021 at 13:04
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    Are you certain that water intrusion is occurring at lower window? A leak at upper window. Could allow migration through wall that shows up at lower unit .
    – Kris
    Commented Sep 8, 2021 at 15:23
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    @Kris it is possible, I have seen water droplets on the top of the window inside, but I don’t see where there water could be coming from. There aren’t cracks directly above it and I recaulked around the top
    – LRitter
    Commented Sep 8, 2021 at 16:12
  • There is some kind of issue at the bottom window, notice how the stucco is bulging, I would want to remove the stucco down to the flashing (note the flashing in this case is part of the window extending out from the window, if the trim is allowing water behind the stucco this can be causing the problem.Since it is showing below the window make sure the weep holes are clear and can release the water to the outside , not sure fill the track with water this is designed to let the water out when rain gets in there, if it’s not draining find and clear the weep holes so the over flow won’t be inside
    – Ed Beal
    Commented Sep 10, 2021 at 20:06

1 Answer 1


The problem you have is that there is no flashing around the window. Caulking will not solve your problem.

Caulking can prevent water ingress but not water travel. It only works where the caulking is applied, and it is only as good as its ability to adhere to stucco.

The flashing you linked to has a flange and a drip edge. The flange should be installed behind the stucco, against the sheathing of the house.

It's important to have the rain-shield (tar paper, building wrap etc.. which is behind the stucco) lap over the flange at the header. And at the sill the rain-shield should be tucked behind the flashing.

The stucco then goes over the flange, and the drip edge sticks out between window and stucco.

You need flashing at every horizontal transition of materials where you cannot lap the shield, so that's at the head of both windows, and at the sill of both.

Ideally the wrap is folded against the sides of the window too, protruding by perhaps an inch, against which the stucco is applied.

For the retro-fitting you'll have to chisel out the stucco, enough to fit the flashing in and scoop it behind the wrap. To then restore the siding over the flange, you can apply fresh stucco or a separate piece of trim (e.g. wood), as long as the trim or stucco is lapped over the flange. And the wrap is over or behind the flange at the header or sill respectively.

To scoop the flange behind the stucco and wrap, it may be easier to work in sections. So for a 24in wide window you can use sections of 8in, and scoop each individually, rather than try to insert a full 24in length of flashing. Make sure the sections overlap by 2 inches, and ideally squirt a bit of caulking at the overlap.

enter image description here

Image from https://www.stucconews.net/questions/question2601.html

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