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Skylight and re-roofing


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22 years ago I installed a Velux Skylight (V606) on a 2/12 roof using the VPL-4 curb mount on a 10 year old shingle roof. Build 6' deep beveled light shaft, etc. Went great, no runs no drips no errors even in driving rains. 10 years later the roof had to be replaced, stripped, ice and water shield by commercial roofer. No leaks in rains, UNTIL driving rains out of the southeast brought water into the room from the attic about 3-4" away from the light shaft, i.e. not directly down the shaft. The water then flowed along the ceiling parallel to the shaft. Had roofer come back, did some stuff, all ok.....until the next driving SE rain (fairly rare in my area). Finally I decided to have a standing seam roof done and this is just completed and what do we get but a driving SE rain and lots of water, maybe a quart in various locations, same areas as described above. So, at 2 AM I went in to the attic during the rain (should have done this years ago, I know.) and I see the roof entry point about 6" from the SE side peak, right over one of those Velux brackets. The water is running down the adjacent rafter until it hits a drip point onto the ceiling insulation. Did the leak actually start at that location? Given wind driven, I would guess, but what is the proper way to deal with this? Pull the cladding off the curb completely, re-do the curb to roof join, seal up good with rubber flashing tape, replace cladding? Clearly the two roofers did not get a good join there if this is the originating leak location. Welcome you pro's thinking and appreciate!

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22 years ago I installed a Velux Skylight (V606) on a 2/12 roof using the VPL-4 curb mount on a 10 year old shingle roof. Built 6' deep beveled light shaft, etc. Went great, no runs no drips no errors even in driving rains.

10 years later the roof had to be replaced, stripped, ice and water shield by commercial roofer. No leaks in rains, UNTIL driving rains out of the southeast brought water into the room from the attic about 3-4" away from the light shaft, i.e. not directly down the shaft. The water then flowed along the ceiling parallel to the shaft. Had roofer come back, did some stuff, all ok.....until the next driving SE rain (fairly rare in my area).

Finally I decided to have a standing seam roof done and this is just completed and what do we get but a driving SE rain and lots of water, maybe a quart in various locations, same areas as described above. So, at 2 AM I went in to the attic during the rain (should have done this years ago, I know.) and I see the roof entry point about 6" from the SE side peak, right over one of those Velux curb brackets. The water is running down the adjacent rafter until it hits a drip point then onto the ceiling insulation.

Did the leak actually start at that location? Given wind driven, I would guess, but what is the proper way to deal with this? Pull the cladding off the curb completely, re-do the curb to roof join, seal up good with rubber flashing tape, replace cladding? Clearly the two roofers did not get a good join there if this is the originating leak location. Welcome you pro's thinking and appreciate!

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22 years ago I installed a Velux Skylight (V606) on a 2/12 roof using the VPL-4 curb mount on a 10 year old shingle roof. Built 6' deep beveled light shaft, etc. Went great, no runs no drips no errors even in driving rains.

10 years later the roof had to be replaced, stripped, ice and water shield by commercial roofer. No leaks in rains, UNTIL driving rains out of the southeast brought water into the room from the attic about 3-4" away from the light shaft, i.e. not directly down the shaft. The water then flowed along the ceiling parallel to the shaft. Had roofer come back, did some stuff, all ok.....until the next driving SE rain (fairly rare in my area).

Finally I decided to have a standing seam roof done and this is just completed and what do we get but a driving SE rain and lots of water, maybe a quart in various locations, same areas as described above. So, at 2 AM I went in to the attic during the rain (should have done this years ago, I know.) and I see the roof entry point about 6" from the SE side peak, right over one of those Velux curb brackets. The water is running down the adjacent rafter until it hits a drip point then onto the ceiling insulation.

Did the leak actually start at that location? Given wind driven, I would guess, but what is the proper way to deal with this? Pull the cladding off the curb completely, re-do the curb to roof join, seal up good with rubber flashing tape, replace cladding? Clearly the two roofers did not get a good join there if this is the originating leak location. Welcome you pro's thinking and appreciate!

Call the installer of the Standing Seam roof and tell him to fix it.

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Seems to me that you need a different roofer to look at it and fix it. Determining where a skylight curb is leaking should be something that can be determined by someone that understands roofs. Your situation requires someone to actually see it.

Also, Velux skylights are good but after 22 years it may be time to update the unit and flashing system. You must be tired of fixing the ceiling under the leak (not to mention that the chronic leak can also be associated with a bunch of other problems like rot, mold, etc.).

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Point taken about the Velux. Still putting a new Velux up on a leaky curb is not smart, so probably fix the curb, i.e. get it flashed or properly sealed out (not just with some caulk) and then put a new curb mount Velux on it. Looks like a VCM 4646 will go up with just a small height difference. Cannot buy a new curb as they do not make the VPL-4 sizing which is 15" inches higher than the skylight....nothing is simple....nothing....

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Skylite leaks begin in the areas you can't see. The most important work occurs before the roof cover is applied. If you can see the problem, then it's total jacklegged nastiness that should all get torn out.

You want lock down, don't leak, fixed that's it forever until the next roof... you're backing up to when the lite gets bracketed to the roof structure, then proceed with copious 40mil self adhered detailed into a drainage path and all other flashing, then the roof cover. Half measures don't work. Any repair solution that involves caulk or mastic....doesn't work.

I know beyond ever being persuaded otherwise that skylites can be installed so they never leak. Any deviation from perfection, they usually leak.

The Velux system is pretty good.

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That makes a lot of sense. Given that it takes 3 years or so to get a wind driven rain from SE, once the work is done is it maybe sensible to hit it with a spray of hose water sideways (not highest pressure necessarily, just a nice spray.)? That way we have at least some sense that the fixes worked.

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Spray hose testing can tell you something, or nothing. High pressure wind driven rain is not replicated with a garden hose.

We put skylites in by visual checks; you can see if it's going to work just by how the materials are installed.

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Makes sense....Based on what you said before, I should probably ask the guy what he did when he ripped up the old shingle as regards the skylight flashing. He should have gone all the way down to the ply, or at least the I+W and the Velux original step flashing should be gone, new I+W and or Flashing tape, then a proper metal roof flashing job, right?

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Step flashing and metal roofing do not go together... not even close. If a shingle roof was converted to metal, the original skylight might not even work, if it's not the curb-mounted type. There are Velux skylights that you screw to the roof and then shingle in, and there are others that you install on a curb AFTER the roofing is completely done and the curb is flashed. I'm not familiar with the skylight type you referenced in the OP so not sure what the install looks like. My opinion is that a curb skylight on a metal roof can be made virtually bulletproof.

Question: what type of metal roofing was installed? 2:12 is a low slope roof for metal, so hopefully you have an appropriate type.

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What David said.

I was assuming you had the base pan flashing for the elevated curb. The curb you're talking about increases the pitch (Velux doesn't want their stuff on anything <3:12, maybe 4:12....I forget), so they provide this base to get the pitch, but it doesn't mention the pan. If the standing seam installer used just the existing stuff from the previous shingle roof, it can't work.

Velux' website instructions are lousy, but they at least imply what you want. Go here, scroll down to Instation Methods, go to Pan flashed (3rd one). Your installation would have this pan, plus the VPL4 pitched curb.

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The only way I've ever reliably flashed any component on a metal roof where that component had greater width than the individual roof panels themselves was to run flat flashing on top of the panels upstream of the component (and the full width of the component) all way from ridge trim to the upper upper of the component.

Marc

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22 years ago Velux required a sloped curb on slopes less than 5/12. 10-12 years ago they improved the glazing system and lowered that to like 3/12. 7-8 years ago they eliminated the sloped curb assembly. There will not be a Velux flashing kit for that curb and any sort of metal roofing. You need a new roof cover and a new curb mounted skylight.

I put a deck mount solar powered venting skylight on my brothers house, 3/12 pitch, corrugated steel roof, Velux metal roof flashing kit. It leaked like a seive. To fix it I had to remove all the steel top to bottom, fill between the purlins with extruded foam insulation, and cover the whole thing with ice and water, 8 feet wide and just over 3 square in area for a light approximately 20x40 inches.

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I retired from my20+ year fenestration career 2 years and 2 weeks ago. Velux stopped making the sloped curb years before that. The last catalog i had they made all kinds of flashing kits for deck mount units, a curb mount unit that left the curb and flashing up to the roofer, a self flashing unit in limited sizes, and a hideous array of blinds and shades.

Products change fast. Plus, in two years I've forgotten more about windows than most people will ever know.

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It was never a very good pan in the first place. We had ours custom fabbed by a CNC sheet metal shop. I haven't done any Velux specific jobs in a few years; you're right, it changed fast.

They used to make mounts for everything, now it's blinds, accessories, and pushing people toward Velux Certified Installers. Probably the smart thing; few ever got it right even when they had the stuff to do it right.

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I will try to get some photos done today or tomorrow and post. The original Velux flashing kits were used for the curb and the skylight itself. That was step flashing on the then shingle roof and the flashing clad kit on the skylight and curb. For 10 years perfect, then at re-roofing to shingle the wind driven issue started and now with the metal re-roof same deal. I will be quizzing the roofer as to exactly what he did. Of course it could be an issue in the skylight itself, something he did not touch in his work. Yes, the skylight crosses several metal sections. I see the point made by Marc, assume he means flashing in each standing seam section, not something over the seams...Roofing Mfg is Englert by the way, which I understand is reputable.

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I will try to get some photos done today or tomorrow and post. The original Velux flashing kits were used for the curb and the skylight itself. That was step flashing on the then shingle roof and the flashing clad kit on the skylight and curb. For 10 years perfect, then at re-roofing to shingle the wind driven issue started and now with the metal re-roof same deal. I will be quizzing the roofer as to exactly what he did. Of course it could be an issue in the skylight itself, something he did not touch in his work. Yes, the skylight crosses several metal sections. I see the point made by Marc, assume he means flashing in each standing seam section, not something over the seams...Roofing Mfg is Englert by the way, which I understand is reputable.

Close. Over the seams too. One wide piece of flat flashing from ridge to component. Fits over the curb flashing. At the bottom of the component, curb flashing fits over the top of the seams ie 'shingle fashion'. That's the basic approach: elevate the flashing to the top of the seam, top of the corrugated, top of whatever metal roofing you're using.

Now, I've never done that before on standing seams, only on most every other type of metal roofing, so some difficulties may come up.

At such low pitch, keep the flashing overlaps long so the wind-driven rain doesn't make it up under the overlaps.

I think its possible that low pitch roof decks and some types of skylights are a bad marriage that can be difficult if not impossible to fix.

Marc

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Marc, the version of your method that my roofers use is to install a head flashing that they call a "back pan" above the skylight curb. It is not installed on top of the panels as you are describing, but under them... but the leg that extends up the roof goes 12" or more. With adequate slope (I'm gonna say 3:12 or more) the top edge of that flashing is at least 3" vertically above the point where the curb meets the deck.

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Marc, the version of your method that my roofers use is to install a head flashing that they call a "back pan" above the skylight curb. It is not installed on top of the panels as you are describing, but under them... but the leg that extends up the roof goes 12" or more. With adequate slope (I'm gonna say 3:12 or more) the top edge of that flashing is at least 3" vertically above the point where the curb meets the deck.

Tell me about the sill flashing.

Marc

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The sides and sill are flashed over the roofing. The profiles are both 1" tall so they can sit on top of the ribs, with a hemmed leg that goes down to meet the field of the panel. The panel is cut and bent up the sides of the curb.

I wish I had some photos. There are two curb-mounted skylights above my head that are flashed into a 12" snap-lock roof, but it's dark right now and way off the ground.

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