Leaking skylight, how to fix
#1
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We have a rectangular velux skylight on the sloping roof(something like one of these, I don't know the exact model number, not sure what deck mounted or curb mounted or self-flashed means)
Yesterday it rained for prolonged time (not very heavily). (rain total for 24 hours = 2" according to local weatherman) After about 12 hours of rain, The top left corner of the skylight became wet and water started streaming down the edge and when enough water accumulated, water drops fell down. (about 15 drops per minute). (The dotted red line in this picture)

The rain ended in 10 minutes. As the rain slowed down, the water leakage slowed down and stopped with the rain. so I didn't have to worry too much about it.
I think the skylight has leaked in past. (The wall has some water damage lines).

Both top corners of the skylight show some water marks/damage. Here is the right corner.

The skylight is openable. (I have opened and closed it once in the summer)
Where is the leak? How can I find the leak? How can I fix the leak?
Thanks
Yesterday it rained for prolonged time (not very heavily). (rain total for 24 hours = 2" according to local weatherman) After about 12 hours of rain, The top left corner of the skylight became wet and water started streaming down the edge and when enough water accumulated, water drops fell down. (about 15 drops per minute). (The dotted red line in this picture)

The rain ended in 10 minutes. As the rain slowed down, the water leakage slowed down and stopped with the rain. so I didn't have to worry too much about it.
I think the skylight has leaked in past. (The wall has some water damage lines).

Both top corners of the skylight show some water marks/damage. Here is the right corner.

The skylight is openable. (I have opened and closed it once in the summer)
Where is the leak? How can I find the leak? How can I fix the leak?
Thanks
#2
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You can find the leak from inside the house. If you go on the roof, you might see something. You can always water test it with a hose, starting from the lowest point & go up.
#3
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Hi tnkrer, if I read it correctly you indicated it was leaking at the top. Unusual since water would not collect at the top. It is possible the glass has shifted down and the seal is no longer covering the gap. You also said it appeared to be happening on both sides so take a look if you can get up there to see if it has a rubber seal and if that seal is still doing it's job. I have limited experience with these so may be entirely out in left field, but usually the glass is not held tightly due to expansion.
Bud
Bud
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Velux is a quality roof window. Their flashing kits do not leak if correctly installed, and in 25 yrs, I have only had one glass unit that leaked. That was easily repaired. That said, what Bud said. A hose should be able to duplicate the leak, but in that location, I would guess that the flashing over the glass unit needs to be removed(not the shingle flashing) and the edge needs to be caulked.