John Schimmoeller
LEED GA
12/1/2015
I'm having standing seam Galvalume installed on a 1/2" in 12 very low slope roof. Due to a measuring error the panels are 7.5" short of reaching the peak. My roofer wants to add 8 to 10" of peak flashing to cover the gap. The peak flashing will be made from the same charcoal gray steel being used to wrap my gutter boards. First, I suspect the bright Galvalume and dark Steel will expand and contract at different rates which could compromise the seal between the two over the years. Couple that with the extreme low slope and this could lead to issues down the road. Second, this roof is very visible from the street and sidewalk and I don’t think reaching the peak flashing 8 to 10” onto the roof in order to cover the short panels will be acceptable aesthetically. My roofer says this is an acceptable range and that it would "pass inspection by any manufacturer". Is he correct or should I request he replace the panels? Are there other concerns we should consider? Thank you in advance for your assistance.
Todd Miller
Classic Products, Inc.
12/1/2015
Making a larger ridge cap is not unheard of ... usually when this sort of thing happens. I would very much want to know exactly how the ridge is going to be flashed. Ask for a drawing. He should be installing Z Cleats between the standing seams and then the ridge, probably a two-piece system, will lock over those C Cleats. The Z Cleats need to be well sealed. This would be a good ridge assemble for a normal ridge, and can also work for this larger wider ridge.
John Schimmoeller
LEED GA
12/1/2015
Thanks for responding Todd.. The roof is just a simple slant with one end 12" higher than the low end, so there isn't a ridge, only a peak. I've attached a photo of the peak flashing detail provided by my roofer. His idea is to extend the flashing 8 to 10" onto the roof to cover where the panels are short. I'm not convinced this would be advisable on such a low sloped roof.
John Schimmoeller
LEED GA
12/1/2015
Here's a photo of the roof in question. The garage panels are 2.5" short of the peak and the adjoining laundry room panels are 7.5" shy of the peak. The home sits down slope a bit so both are very visible from the street.
Todd Miller
Classic Products, Inc.
12/1/2015
Thanks. You will have to make the determination as far as aesthetics. The drawing you have posted does show the use of Z Cleats. The predominant expansion / contraction of the panels themselves will be vertical on the roof and the predominant movement of the flashing will be horizontal. The Z Cleats are used so that the peak flashing can slide or float horizontally. Because the Z Cleats pin the metal roof panels to the roof deck at the top, the expansion of the panels themselves is downward, not up toward the peak. I am comfortable that installing this larger peak flashing presents no greater chance for problems than would the same flashing installed on a smaller scale. So, from a technical standpoint, I am fine with it. You will need to make the call from an aesthetic point. I assume that the metal roof panels being installed are approved for this low pitch?
John Schimmoeller
LEED GA
12/1/2015
Thank you very much for your helpful input Todd. Yes, the panels are recommended for low slope. They are Pac-Clad Tite Loc Plus: https://www.pac-clad.com/metal-roofing/tite-loc-plus/ I understand how the Peak Flashing can be used to "fix" the problem, but I'm still having trouble accepting that panels 7" short of covering my roof are just as acceptable as if they were measured to fit properly.
David Stermer
12/1/2015
Hi John, Here are my 2 cents worth. I agree with Todd that a long trim should perform as well as the original detail and is a common fix for this sort of problem. The concern I have is if someone were to step on the peak trim, especially at so low a slope, it may collapse, as there does not appear to be fasteners securing the vertical leg - just a 'keeper'. I recommend adding a Z, as high as practical upslope of the end of the panel to support the peak trim under such a load. Some sort of fastening /adhering of the trim to the Z would be appropriate to avoid roof noise. Regards, David Stermer

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