Water Testing for water ingress and 
window leaks 

Where is leak from ? With windows, the leaks can come from a variety of locations. However many times they are not from the actual penetration itself. Window nailing flanges rarely leak, therefore usually the leak is from above or from the window itself. 

Installation or window unit . . .  To rule out the window, seal it off from the penetration by taping poly to the frame. After the test  the poly can be removed and the window  itself can be tested.

Upper windows that are installed with the lower paper flap behind the wall membrane allows entry into the lower window via joints in sheathing. 

We use a blower door to depressurize the house when doing water tests to simulate wind against the building

Soffits  weather barriers missing from behind soffits and insulation stops are a common source of windows leaks. The house to the left had windows leak when there was wind driven rain

After water testing we determined the soffits were the source. To confirm we did final destructive test and found the paper was lapped incorrectly as seen below

Verify  To reduce destructive testing when not necessary verification can be done using infrared thermography, moisture meter or straight visual inspection.

Destructive Testing
After we are sure of the water path a destructive test can be conducted by opening the location and viewing both the source of the leak ( i.e. lap issues with paper) or the damage resulting. This can be documented for forensics or repairs
Water in . . .  Water out . . .
The window on the right had been sealed on all 4 sides of the flanges with a rubberized membrane that prevented moisture that got into the window rough opening from escaping
Where is leak from ? Water entry into the wall cavity does not always present as a leak.

Stucco cracking and discoloration, drywall cracking, wet carpet, staining on ceilings also provide indications that water is entering.

DON'T WAIT - get it checked

Water from soffits above
Water from window unit itself
Water from upper window
Since 1986

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