How to Fix? Water Coming in Around Windows & From Above? What Roofing or Other Issue is This?

Updated December 11, 2020
beige home with single driveway
Photo: Iriana Shiyan / Adobe Stock

Question by Guest_9062529: How to fix? Water coming in around windows & from above? What roofing or other issue is this?

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Sometimes when it's raining (and even when it was below freezing & snow outside), we've had water dripping inside a bedroom window. (It's a slight dormer window in a sloped mansard second-story roof). Causing plaster around window to bubble and creating bubbles and cracks in the paint in the ceiling below. Definitely coming in from above as we can see the water dripping from the top of the window and down the pane & blinds. We have new windows. So frustrating. Our roofer caulked around the window but that didn't work. It 'rained' inside again since then. We think it may be nail holes in the roof above the window (heat inside the house may be melting snow? only sometimes? don't think it's condensation as pretty heavy drip when it happens) or some flashing that wasn't done correctly. Appreciate any insights on what this is and how best to fix it. It's not yet time to replace the roof.

Answered by WoWHomeSolutions: Get your roofer back out there. Course of shingles above the window need to be pulled, self sealing flashing, drip caps, and counter and step flashing are going to be required here.

This is a flashing issue as the window connects to the mansard roof surface.

Condensation and a leak are two different and very noticeably different (i.e. volume) things.

Flashing and roofing on Mansards can be tricky but is sounds very much like a roofing issue.

Answered by LCD: 1) Do you have an accessible attic where you can get up here and look at the underside of the roof sheathing aboveand aroundthe dormer ? If a main roof or flashing leak running down and exiting at the window, you should see water running down the underside of the sheathing, and staining. If none there, then that leaves you with the dormer roof and flashing, the window itself, or siding above the window, which are more likely unless you have a flat-topped dormer.

2) Since you say it occurred in snowy conditions, that should rule out a leak at the window itself unless it has a large projecting top brow ledge that can hold snow, and also siding issues unless you are missing entire pieces. Ditto if happens during snow melt but when there is no active precipitation falling. If you have a peaked or domed dormer roof, pretty much leaves dormer roof surface or the flashing around the dormer - and since coming in at top of window, sounds like roof.

3) Also, except in VERY cold weather, you would not get enough frost buildup in an attic, in general, to cause enough of a drip when melting to make it down the wall to the next floor ceiling. Also, this frost melting would occur during a thaw after HARD freeze spell (typically below about 10 degrees F), not during rain and warm snow conditions also. Pure condensation, without frost buildup to allow it to build up thick, rarely makes it past the point of molding insulation and forming mildew on attic wood, and VERY rarely gets to the point of flowing anywhere more than a few little drips trickling down the underside of the roof sheathing. Can certainly cause attic problems, but I have never heard of it (except from condensation on inside of window glass) causing this sort of significant wetting, and you say drips from top of window so certainly not that.

4) I am assuming you have a peaked roof - if flat-topped, then I would bet it is leaking on a flat part and running down the sheathing or roof underlayment to a point above the eaves, and the roofing is terminated wrong there so it is coming down through the roofing above the eaves into the wall.

5) Have you checked gutters over the dormer, if you have any, that they are not blocked up and getting backup into the roofing edge and down into the wall. Generally a dormer would not have gutters, but if you have a flat-topped dormer with gutters, then that interface would be highly suspect - more so than the possibility of a roof leak further up the roof migrating down and just happening to come out at the window. Worst possible case would probably be something like this, a flat or inverted V roof with a flat-topped dormer - like the 31st photo down as I count it, with this caption - This mansard roof on Central Street has a convex profile.-

6) A sure way to tell - I tend to be a "dig in there and find the darn source of the problem" kind of guy - since the drywall is damaged already, carefully with a utility knife remove damaged drywall right above the window frame, opening it up till you can see where the water is coming down - inside the wall (and on which face - inside drywall or inside the siding), or coming in from outside at top of window frame. That would be pretty definitive, and if coming from above the window you could open up a strip of drywall up the inside of the wall (assuming you do not have fancy interior walll treatment that cannot be matched) and "chase" the leak to the ceiling to see where it is coming down the wall. If you have fiberglass or blown-in insulation, you do not even have to open much of a hole - reach up in a small hole and pullthe insulationn abovge the window out, then use a strong flashlight and mirror to look up into the wall. Could be a leak right above the window, or if you have vapor barrier above your ceiling, could be a leak further upslope on the roof or in the flashing dripping down onto the vapor barrier, then flowing to the low spot and pooling till it overflows - which might just be above the window.

7) Please let us know what you find the problem to be - so we can improve our advice for other questioners down the road. Answering questions like this tends to be a bit of a ouija board operation - we try to avoid getting into a case of the blind leading the blind, but without a hands-on look-see or photos, can be tough to give accurate advice.

Answered by ContractorDon: I just gave a plus to one of the above answers but I have to add to it. Caulking around the window seems like the right answer but a window in a basically roofing situation has to be thought of as more of a part of a roof and not a wall. Your window guy has to think more like a roofing expert or vise versa and chase the leak to above where the water is getting in. If you have a good eye it is sometimes easier to find where there is no leak and work down from there. Caulking a joint on a problem is generally a way to say I have no idea where the leak is!Don

Answered by Guest_9062529: Thank you all for your help! The roofers have come out multiple times and didn’t see anything. At our request, we asked them to look again at our attic (they and another roofer have often just wanted to look at the roof & window from the outside) and this time, they saw what we think might be the problem. There is a ventilator/power fan that was disconnected. Also, there may not be clear air intakes from the outside to help circulate the air in the attic. We also have a whole house fan that likely brings warm air from the house up into the attic which is a no-no. Apparently, the attic needs to stay closer to the temperature outside with the insulation on the attic floor. With the whole house fan, there is a big slotted cut-out in our ceiling and warm air easily escapes into the attic. When it's cold outside and moisture accumulates due to the poor ventilation and from difference in temperature above & below the roof, a frost forms on the underside of the roof. The warm air from the house, particularly on cold days & when we’re running the heat, melts the layer of ice which drips down and seems to run around the window/s to escape.

So, it looks like it is a ventilation problem. And, we need to create an insulation blanket or insulated box to place over the whole house fan ceiling 'cut-out' in the winter. We also likely need to reseal/create a barrier where the water used to run around our windows to fix that as well.

Fingers crossed. I hope it works. Plugging in the old power ventilator or adding a new one. Potentially adding new vents (intakes and potentially outtakes). Reinsulating the attic floor. Repairing attic/window damage & creating new barriers where the water used to flow down and around the windows.

Source: G.S. Reilly

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