David Metzger
3/27/2015
I have concerns my entire roof is leaking due to improper detailing of my standing seam roof. Please look at enclosed photos. Some details: I have a shed roof with a 3 1/4: 12 pitch. 1" single-lock standing seam. R-50 insulation in cathedral ceiling. Hot roof: Fully Zip taped, Zip sheathing and GAF underlayment. Conditions: Lots of snow build-up over winter. Eventually ice builds-up over top of the seam. As weather gets warmer, water is observed dripping out underneath of overhang on low part of the roof. My guess is the entire roof is leaking at the standing seams and water is sheeting down roof plane, over underlayment. Question: Will a double-lock fix this problem? Or should roof be replaced? This is a 1.5 year-old roof. Many thanks for your help and suggestions!
Info @windowsonwashington.net
An informed customer is our best customer.
3/27/2015
Double lock would make the seam a tighter and less likely to allow the water to bypass the panel lock. Really need to know where the water is coming from first. Any chance you can pop open the overhang? I would incorporate some heated cables to control the ice dams before replacing the roof.
Guest User
3/27/2015
My fear is if I double-lock the seam, I'm committed to the detail and it may still leak. At this point--with a single-lock--I could probably take it apart piece by piece and mitigate the problem. Roofer suggested I clear snow off--which is not a long-term solution--it's just plain dangerous. It's also a "green building" so plugging my roof in with heat cables to clear the ice all winter is also not an ideal solution. I'd like a 50 year solution--which is why I got the metal roof! Popping off the tongue and groove soffit would probably be more damaging than popping off a roof panel. That said, it was rolled on site--each panel is 30' long. Having done some research, a 2-3" tall standing seam with a butyl sealant at every seam would have prevented this from happening. As it is now, if I can take apart the roof, the solution could be covering the Zip sheathing with a waterproof underlayment, then redoing each seam with sealant and a double-lock. BTW, there are no penetrations in the roof to cause this leak. I feel, based on the ice building up over the seams, that leaking through the seams is the only likely cause. Enclosed is photo from soffit side.
Info @windowsonwashington.net
An informed customer is our best customer.
3/27/2015
If the roof did not incorporate some rigid foam to the exterior, the thermal bridging of the framing will probably be enough to melt some snow. If you are going to re do it, some rigid foam to the exterior will help mitigate that heat loss and melting. Are you sure the water is coming from the roof side and isn't from any ice in the gutters that is backing up behind the starter/eave metal?
Guest User
3/28/2015
There is no ice anywhere near the gutters. The ice simply builds up over the seam--look at the photo. It doesn't flow off the roof except in liquid form. I think if snow is left on a roof all winter in a cold climate, eventually the laws of physics says there will be ice build-up between the roof plane and the snow above (the structure are I-joists that have minimal thermal transfer). The problem, as I see it, is that my roofing contractor says standing seams don't leak. Well actually, they do if they are not detailed correctly. And for a low-pitch roof you need over 2" high seams, butyl or some kind of gasket on the full-length of the seams, and as a second line of defense, a waterproof underlayment membrane covering the sheathing. None of these details were done by my roofing contractor, and now my very expensive standing seam metal roof is leaking. So the question is what can be done? It's an interesting riddle.
Info @windowsonwashington.net
An informed customer is our best customer.
3/29/2015
Fixes - double lock seam - taller seam - rigid foam on the roof deck with stagger seams - above deck venting - synthetic underlayment - 6' of ice and water (non-granulated) at the eaves
Guest User
3/30/2015
Hi Eric, Thanks for your recommendations. There's a new theory about the leaking water which adds a whole new layer of mystery. The water started dripping on the first warm, rainy day. It's possible that there was massive condensation building up on the underside of the roof plane in the 3' uninsulated overhang (soft). The ice on top and the warm, humid air on the bottom. The only way to confirm this is to remove part of the tongue and groove wood soffit next winter when this condition happens again. As it is now, all ice has melted away. Of course I could also remove a section of my roof to see if there is any evidence of water intrusion, but that seems ridiculous at this point. I've attached a new photo showing the house and overhangs. And by the way, my roofing contractor shows no interest in taking any responsibility for my roof leaking. His only response to me is that standing seams don't leak and that I need to shovel my roof off...
Info @windowsonwashington.net
An informed customer is our best customer.
3/30/2015
Pull some soffit. That is entirely possible with that deep overhang and the right collection of temps. Eric
Dick Bus
3/30/2015
David, you mention that you do not have any penetrations in the metal roof. is it possible that the venting is being 'dumped' in the overhang? does the leaking that you are seeing only occur in the overhang or in the interior of the home also? were you able to determine if the leaking was in a concentrated area or the entire length of the house? the amount of snow you are getting in that part of New York, I doubt a higher seam high will make that much difference.

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