I can't find the source of the leak around this skylight

Hello great people of roofing,

I’ve been dealing with this leak for months and haven’t been able to fix it. I’m not an expert, just a new homeowner who should’ve been more careful. As you can see in the pictures, I recently had a repair job done where the contractor applied Firestone app 160 membrane all around the skylight and on the side of the damaged chimney and also some flashing cement in a few places around the rest of the roof. The leak seemed to have slowed down at first but the repair didn’t really fix anything as you can see the state of the ceiling of the bathroom where the skylight is installed. After the so called repair the contractor opened up a bit of the ceiling to see where the water might be coming from but he couldn’t really see much. He’s suggesting it’s coming from further away somewhere on the roof and trickling down through the skylight or that the skylight was installed wrong -against the pitch of the roof-. So he’s saying we need to apply membrane on the whole roof. (around 250sq foot, asking for 7500k, not sure if it’s ok to ask about pricing here)
Also do you think it might be the old chimney? He said water isn’t coming from there but I’m not sure I can trust him.
I would love to get an experts opinion on this. !
(upload://zaRkCuxuCEXaLBMlwrNJ7dXBMvc.jpeg) ![roof|279x500]

If you want to experiment, put a diverter (2"x2" L metal) above the skylight to shed the water away. If the skylight still leaks you know that water is coming from above the skylight under the membrane or through the skylight flashing. I can’t see the flashing used for the curb of the skylight which might be the source of the leak.

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Sorry for your troubles. It looks as if the roofer tried, but we see this often; trying and doing it the right way are two different things. The work doesn’t seem like it wasn’t good intended, but rather without knowledge or proper training. Firstly, no one should ever do that to a fireplace: absolutely absurd! Your gas exhaust vent is also missing its storm collar, but that is certainly not the source of big leak. That skylight area should have probably been pulled, where the underlying wood substrate was inspected, and a new roof system was applied to the area -to say the minimum. It’s hard to see exactly what’s happening with the pictures, but it looks as if that is an exposed base sheet, with some patching material atop. I would say you need to hire a qualified roofer to pull that area, provide build-up, and replace what appears to be a Velux skylight, but a complete roof replacement is really what’s in need. We are located in Tucson, AZ. but install flat roof systems all the time, which are then coated in elastomeric to reflect the heat. We also charge about $6-7 per sq. ft…not $25 as the other contractor proposed. Of course there are many variables to this, including access, minimum fees for setup, etc…but that quote seems nuts! The only bids that high I have ever heard of come from the NYC area…maybe that’s where you are. If you’d like, I’d be happy to assess your bids via my email at info@azroofwork.com -to provide assistance. Our website is https://azroofwork.com/ We are Southern Arizona Roof Associates, LLC. ROC#317034

I certainly would not allow someone to restore that roof as you mentioned…it looks like it needs to be pulled and replaced brand new…I’ll also add that the Velux skylight could have lost its seal…a new Velux skylight, standard, fixed curb mount retails at $239 for a 2’ x 4’ unit and $182 for a 2’ x 2’ unit…material only. Home Depot sells them at the customer service center (special order), and your skylight has a metal tab located under the top glass for identification and matching purposes. Perhaps a call to your local roofing material houses could help with a good referral too. Good Luck! Send me your bids if you’d like…I’m a real person! We have been told by our website builder to join blogs for our SEO results, so maybe this is a win-win! This is my first post!


It looks like the leak is at the skylight corner.
But he could be right if that is a cathedral ceiling.
The leak would be close though…
Straight above it( not sideways)
Is that a chimney right above that leak?

Not sure how long the light has been there. Looks like a pan flashed light. I know velux requires 3/12 for horizontal install. Really needs a curb mount. Just my observation.


Good point rooferama and to expand, a curb mount with pitch built in.

Not sure how big that roof is but the small corner we’re seeing has a skylight, chimney, seams, and pipe jacks sealed. Maybe time for a reroof?

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He didn’t burn off the aluminum coating adequately, the patch may not being fully adhered.


Hi Dan

Thank you for your detailed response and good luck on increasing your SEO. My main objective is to fix this issue without having to replace the entire roof since there haven’t been any problems elsewhere but of course can be. As you assumed correctly, the house is in NYC and the prices are indeed astronomical. So besides a new roof, your suggestion would be to replace the skylight. Do you think it might be better to just remove the skylight entirely and level the area?
Also the chimney doesn’t have any function as there are no fireplaces in the house. Do you think it’s appropriate to remove and level that area as well?

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It was installed a year ago. Does a curb mount involve the removing and installation of a new skylight?

Yes it does, it is a different type of skylight.

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The ceiling is flat so I don’t think it’s a cathedral ceiling. That is a chimney close to where the leak is. Since it’s not in good shape and has lots of cracks, the roofer thought it’d be best to apply membrane on its side as well. Though I’m not sure that helps much.

Perhaps find a different roofer.

None of the pipes are wrapped in membrane and are reliant on flashing cement.

The not burning off the aluminum coating is a big deal since pretty much nothing sticks to it.

It looks like you have an inexperienced roofer.


as donl said,if theres no flashing around skylight itself it might be leakign thru the sides ?,raise curb to 6" and slap some flashing to eliminate light then possibly you have chimney,pipes,or untorched areas at seams.imma would do this step by step,it might take you two three times,but for sure it will be fixed instead of guessing.

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Removing the skylight and chimney will be a successful repair.

I wouldnt charge you an arm and leg to do it.
But that is subjective.

It is the type of repair that makes a roofer smile and be confident he will fix it
And charge a lower price.

My price would be significantly lower because i would be charging significantly just for the warranty if i needed to replace the skylight, its surrounding roofing and guarantee the watertightness of the old chimney fluke.

Example- replace skylight, its surrounding material- $2000
Remove skylight, chimney fluke, fix leak-$1000

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In pics, what direction is downslope? What is the new pipe in the 3rd pic, appears to be duct and not a “B” vent, bathroom exhaust maybe? Did the leak move or change in volume after the repair? What is the airspeed velocity of an unladen swallow?

What do you mean? African or European swallow?
It’s a flat roof. That doesn’t mean it doesn’t have pitch I guess but I don’t know which way the pitch is.
The skylight is on the ceiling of a bathroom so yes I think that’a bathroom exhaust.
There was no noticeable change in the leak after the repair.