Skylight Flashing

[Duckslapper]

A friend asked if I could help her with 2 leaky skylights. She just bought the house over the winter and it was re-roofed just months before she bought it. Now that spring is here, she's discovered water stains all over the ceiling. Anyone familiar with how these units are supposed to flashed? I expected step flashing but that doesn't appear to be the case.

 

[Slowgsr]

Do your best caulk the rest ?

 

[NeubCont]

Let’s start with the flashing (if any) would be under the shingles going up the sides.
Can’t tell with the pix you posted.
Almost all of the skylights I repair is the flashing on top of the skylight.
You would need the lift and or remove the shingles on top.
Then post other pix to further assist.

 

[kd3pc]

supposed to be flashed to the roof, then membrane or felt, flashed again so that the first flash is under the next flash going up the roof...all joints are running down hill so any water flows over the next one down hill towards the gutter or roof edge. Once all that is properly done, then shingle as close to the skylight but NOT nailing through the previous installed flashing.

Given the new roof, I would be searching for the company that did it, or at least asking the realtors to get involved for that company to provide warranty work if at all possible.

Going forward, explain to her the fewer holes in the roof the better. And if she buys another house, to get all of the recent paperwork about things like HVAC, shingles, etc. OR adjust the purchase price and do all this on her watch.

Many times sellers have the cheapest work possible done for the sale.

 

[Duckslapper]

Let’s start with the flashing (if any) would be under the shingles going up the sides.
Can’t tell with the pix you posted.
Almost all of the skylights I repair is the flashing on top of the skylight.
You would need the lift and or remove the shingles on top.
Then post other pix to further assist.

Thank you. I'll see if I can lift the shingles on top and get a few more pictures.

 

[Duckslapper]

supposed to be flashed to the roof, then membrane or felt, flashed again so that the first flash is under the next flash going up the roof...all joints are running down hill so any water flows over the next one down hill towards the gutter or roof edge. Once all that is properly done, then shingle as close to the skylight but NOT nailing through the previous installed flashing.

Given the new roof, I would be searching for the company that did it, or at least asking the realtors to get involved for that company to provide warranty work if at all possible.

Going forward, explain to her the fewer holes in the roof the better. And if she buys another house, to get all of the recent paperwork about things like HVAC, shingles, etc. OR adjust the purchase price and do all this on her watch.

Many times sellers have the cheapest work possible done for the sale.

Thank you! From the two pictures I posted, would you think the step flashing is suppose to go tuck under the brown steel trim that wraps around the skylight? In other words, after its flashed that brown trim goes over it for a cleaner look?

I was thinking after removing the old shingles they may have just shingled over the old step flashing instead of redoing it and having it feed out onto each shingle.

 

[ddawg16]

If you do it before it gets too warm, they won't be stuck to each other.

I'm willing to bet the the paper on the sides is on top of the flashing....

IIRC....the paper should be on top of the flashing at the top....but under the flashing on the sides and bottom.

If the paper is on top of the flashing on the sides, even if caulked, the water runs down the flashing and seeps under the paper.

 

[chinboys]

Step flashing along the sides.
May need a cricket to divert the water flow away from the top of the skylight. No, a high curb only means the water doesn't overflow the top of the light but doesn't do anything for water being backed up at the curb from back flowing underneath the rows of shingles near the top of the skylight. The top of the skylight's flashing only is good for 2 rows of shingles hence proper water and ice flashing is required to surround the skylight at least 6 feet around.

 

[strutaeng]

Are the water stains new? Maybe they have been there and didn't notice them until now?

I have a Velux fixed 46x46 skylight curb mounted unit. I bought the kit sold by Velux which included upper and lower flashing, step flashing for the sides and roll of underlayment peel and stick. Roofer didn't install the peel and stick, but it doesn't leak.

Is that perhaps a specific-made skylight? Is the actual glass leaking?

I would think you need step flashing. On mine the step flashing goes all the way up to the curb and the units goes over that. Maybe you need to get some custom step flashing and cut to fit under that drip edge.

You can use a garden hose up there to simulate rainwater to help you find the leak.

 

[strutaeng]

This might help illustrating the flashing components:

https://images.homedepot-static.com/catalog/pdfImages/3e/3ec72a09-794f-4bee-9292-347351f86c96.pdf

 

[NeubCont]

Ddawg16
Spot on
Strutaeng
Great illustration
As I stated in my post
Need to see some pix of the side flashing but most important is the top flashing!
Almost all of my skylight repairs are because the top flashing does not have the felt or water shield over it. (Snow and ice shield is another debate for another day)
P.S. Some skylights have flashing already attached to the skylight (no step flashing)

 

[DIYDave]

VELUX make their flashings for flat roofs, or what is considered flat (under 15 degrees) so complicated!

 

[theoldwizard1]

The most important piece is the top piece. It is best if it is one piece, "made to size" and wraps around the 2 corners. I would also use ice/water shield to stick it to the bare wood.

Step flashing down the sides let water out at each course.

Properly done, caulking is for "neatness".

 

[nmk_61802]

Bottom flashing looks installed under shingles. Water coming down sides has no where to go but under the shingles. Bottom row of shingles should be under the flashing.

I would start there

 

[Duckslapper]

Thanks for all your help guys! I went back for a closer look and found it was flashed, just not correctly. Nails through the step flashing below the upstream piece, about every 3rd piece didn’t feed out on top of a shingle, and the bottom flashing had half a shingle face nailed on top of it. It rained today and water was actually backed up at that shingle.




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[matt_i]

Good find! and nice photos to document it too

 

[DIYDave]

Thanks for all your help guys! I went back for a closer look and found it was flashed, just not correctly. Nails through the step flashing below the upstream piece, about every 3rd piece didn’t feed out on top of a shingle, and the bottom flashing had half a shingle face nailed on top of it. It rained today and water was actually backed up at that shingle.




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Great find! Fingers crossed you can now sort it!

Still find these flashings for the VELUX units way over complicated, maybe I am missing something.

I just did a skylight on my garage roof, its a felt roof and it's only a fixed one but it was simply a timber upstand/curb with felt lapped up and over the top. Sealed and done. Then the glass skylight secures directly to the top. I will get an image and upload it soon, but these are units I use for this kinda setup flat rooflights

Plus I think them VELUX upstands for the flat roofs come as a kit, which is all precut timber? So requires the roofer to build it onsite. Meh, either way glad you are fidning the leak!

 

[NeubCont]

Those pictures definitely help.
Would still like to see the pix from on top of the top flashing.
Very critical part of the install.
The nails through the step flashing is an easy fix, it is the top flash I think is the most concern.

 

[05r50]

Had similar trouble with low pitch roof with multiple skylights. Over time each one would leak and I would find someone to fix. But it always came back.

All my units were from Velux and I called them at some point and they sent a factory rep out because they guarantee their product when installed correctly.

Mine were not installed correctly. But company was very helpful.

The final fix was I found a factory approved independent installer. One look at the units he could tell me what year they were made and that Velux had an issue with quality back then. (1996 ish made).

I opted to replace all the units and he installed correctly. No problems since.

Also, Velux step flashing is not to be nailed thru the face to the roof. Only the vertical sides against the unit. Also shingles should not be nailed thru the face of the flashing.

 

[Slowgsr]

Those shingles look like their cut too tight to the edges of the skylight too. Crickets are great, or a backpan to shoot water one way, most shinglers can't make them, or make custom flashing period.

Make it watertight by design.

 

[Milton Shaw]

We would be in a lot of trouble world wide if the skylight is "flashing." That would be the sun going out and restarting, like a bad light bulb. Glad that is not happening. .. LOL Global warming would be just the least of our problems.

 

[NeubCont]

Whaaaaaaaaaaaaaat?
No help