Water leaking in above window

Old 10-08-05, 06:44 AM
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Water leaking in above window

Discovered that water is leaking between the boards that compose the window header. Once the storm subsides I plan to remove the vinyl siding above the window in hopes of discovering the water entry point.

This is my first vinyl sided house and my first set of vinyl windows. So I'm trying to compose a check list of what I should look for, how to's and or supplies I should have on hand.

Any help would be much appreciated.
Old 10-08-05, 07:07 AM
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Water leaking in above window

Vinyl is not really your main weather barrier. Problems just show up faster and easier with vinyl siding since it provides minimal protection. The water could be penetrating at any point and running horizontally to where you see it. Does the wind have an effect on the amount of leakage showing up?

Look for improper window installation (probably 90% of the time this is it). The weather barrier, tyvek, tar paper, etc, should shed the rain. Look for proper overlaps (horizontal and vertical), gaps, omissions. Depending on the window type and wall construction there are recommended installation methods that you can find on-line or from others on this forum when you have more information on your conditions.

It is surprising, but it is estimated that over 50% of the windows are installed improperly. Now there is even a certification for window installation that some builders require for their employees or subs that install (cheap insurance in the end). Many reasonably good installers are too proud or busy to go and learn the details and reasons.

Take a good look at what you have and report back with the details if you do not find what appears to be the problem.

Old 10-08-05, 08:45 PM
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Most often, water enters above windows because the windows were installed right on top of the building paper, without flashing the head of the window behind the paper. Many builders now use peel and stick membranes to seal the flanges of the window to the building paper on the sides, and use it to seal the flange of the window to the sheathing on top. The building paper then lays over the top of the flange and is either taped or skip taped.

If there is no soffit above this leaking window, or there are vertical j-channels above this leaking window (from another window, dryer vent or roofline) that's likely where the water is entering. The best way to prevent this from happening is to flash the bottom of vertical j-channels so that they weep water over the nailing fin of the first possible row of siding (using a wide piece of trim coil) so that water is directed out to the siding weep holes as soon as possible. Additionally, making sure the heads of the windows are properly flashed as mentioned above will help prevent leaks.

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