Q&A about building siding, window or wall leak detection, diagnosis & repair procedures.

This article series describes the discovery of both active and prior leaks through a building's walls or windows and the steps that were taken to evaluate the impact of the leaks on the structure, to track down the leak sources, and to fix the problem both in stop-gap mode (due to weather and time constraints) and as final repairs were made to stop future leaks.

Window or Wall Leak Diagnostic Q&A

These questions & answers about how to track down the source of leaks through building walls or around windows & doors were posted originally at WALL / WINDOW LEAK DIAGNOSIS - be sure to review the dignosis and repair steps given there.

On 2017-04-21 by (mod) - newly installed window leaks moisture on one side

Sounds as if flashing and sealant or housewrap were omitted or improperly installed.

On 2017-04-18 by hall

newly installed window leaks moisture on one side to form ice on the outside of the building beneath one end of the window

On 2017-01-20 by (mod) - inspect outside at and above and to left and right of the damp area

Don

Generally I inspect with care outside at and above and to left and right of the damp area for openings, flashing errors, missing sealant at openings, etc.

Then I see what plumbing is in, near, or above the same area.

I might, depending on the level of dampness, risk, concern and external visual clues, use a borescope or cut an inspection opening into the wall to see how wet or moldy - or hopefully not - it is.

On 2017-01-20 by Don

dampness at lower right section of drywall on inside of room, not sure where leak is coming from

On 2016-12-08 by (mod) - Provide a window pan flashing and remember to *not* seal up the water exit point

Phil

Thanks for the helpful comment. We agree. Providing a window pan flashing and remembering to *not* seal up the water exit point are key steps in avoiding leaks into the wall below a window.

On 2016-12-08 by Phil Magnetti

There are two types of windows those that leak and those that are going to leak in the future. Flashing is important so is the type of house wrap. If the unit itself is leaking the house wrap and the flashing are not the issue.

We always install custom fabricated stainless steel window pans under all door and window installations.

If the window or door leaks the water is directed out of the framing to the exterior. Tyvek is not waterproof. Best to use double jumbotex felt paper or Vycor Envy-S house wrap that breathes to allow condensation to escape and it seals around nail penetrations.

On 2016-02-22 by (mod) -

The windows need to be inspected from outside, the leak point found, and depending on the type of wall construction and siding installed, sealed.

On 2016-02-22 by Fatima

I have two windows in my bedroom and both of them leak in water from the top where it meets the plaster on the wall and dripping all the way down and the wall is soaking it up showing a white coating on certain parts please give any advice thanks

On 2015-10-22 by Brian

To Whom It May Concern:

After living in our house for two or three years, we noticed that the paint was delaminating inside our house on both sides of our front door and both sides of our rear sliding glass window.

The problem is becoming severe now with the dry wall crumbling, and it is starting to look like termites have attacked. I tried putting caulk all around the sliding glass window and the threshold of the front door, but you can still feel moisture when it rains, as if that made no difference at all.

The house is stucco and the indoor floor level is about four inches above the outside concrete. There is no soil where the water is leaking in.

A neighbor said I should clean around the bottom of the wall where the wall meets the concrete pavement outside and then apply caulk all around where the wall meets the concrete.

Frankly, when my neighbor gave that advice I thought it sounded really weird and "what kind of crap house must it be to require caulk on the outside wall" with no visible cracks or flaws. I still think is sounds weird because there are no visible flaws. So the builders forgot to apply caulk to where the wall meets the concrete?

There is something seriously wrong, but is my neighbor right? I would have thought there was a more fundamental issue. The house is about 15 years old, and the problem seemed to start all of a sudden, after we have lived in the house for two years.

On 2015-09-10 by (mod) -

John

You should not need to move the window, rather we need to find the point of leakage.

In addition to leaks at the window interior sill that can send water into the wall, any defect in window flashing or house wrap at any of the four exterior sides of the window can also leak into the wall cavity.

I don't urge this except as a last resort, but indeed I've sometimes had to pull off siding around a window to find the water leak stains that in turn told me exactly where the problem occurred. Try sealing all of the obvious openings first.

On 2015-09-10 10:31:32.855206 by John

I have a leak coming from bedroom window which flows through cavity creating a wet patch in the kitchen. The window is a solid wood frame, appears water tight from outside. I have also recently applied more sealant as precaution. All brick work around window is well mortared and secure. Testing with water still produces wet patches in kitchen when pored onto bottom corners of bedroom window. What can the cause be. Do I need to move the window an inch, or so further forward???
Many Thanks

On 2014-09-25 by (mod) -

Bg
You can but I would not use fiberglass as insulation in location where water may leak-in or blow-in and accumulate. Nor would I use a design that offered free housing to mice or other critters.

On 2014-09-22 y bgeboy06@gmail.com

Can I install fiberglas insulation on outside of basement windows and cover with plexisglas caulked on vertical sides only and let moisture escape thru bottom of window with no caulk to stop moisture from getting out?

On 2014-06-24 0 by (mod) - not normally need to remove a window to clean the effects of a leak

janet you would not normally need to remove a window to clean the effects of a leak below it unless the leak went on for so long that it rotted the structure.

On 2014-06-08 by janet humphrey

we have a moldy smell in the bedroom. Fixed a leak at the corner of window. Opened up drywall under the window sill, removed installation , sprayed, placed new drywall but smell is still there. I am afraid that it is under the window. It is a large picture window with to side windows, all one piece. Should I remove the window and replace under it.

On 2013-02-09 by Mike Miller

I also have a leak at a window (or 2) Am trying to get a path forward. Although semi-capable i am certainly no expert on window flashing, caulking, etc. I want my leaks fixed. Who do I call/ contact for help? Had exterior siding re-done (with new house-wrap). Had new windows installeded. got better but maybe just because no driving west wind rain lately.

...

Continue reading at WALL / WINDOW LEAK DIAGNOSIS - topic home, or select a topic from the closely-related articles below, or see the complete ARTICLE INDEX.

FLASHING WINDOW DETAILS

Or see WATER ENTRY in BUILDINGS - home

WINDOW LEAKS INTO BASEMENT

WINDOW SASH REPAIR for more examples of finding leaks and rot in and around windows

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INDEX to RELATED ARTICLES: ARTICLE INDEX to BUILDING LEAKS & WATER ENTRY

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