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TOPIC: Installation Process

how to handle a change in pitch

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I am building a new house in Lexington, Virginia and am looking to use a coated standing seam roof. The issue is that I have a "gullwing" where the pich changes from 6/12 over the house to 3/12 over the surrounding porch. I am getting conflicting advice from various contractors. 1- that I need to end one roof for the house and start a separate one immediately below for the porch. This means cutting across the entire panel. With the snow over the heated house melting more than over the unheated porch, this seems a bad idea as an ice damn may form and the cut may have meltwater over it for extended periods. 2- that a notch should be cut in the standing seam at the bend where the pitch would change from 6/12 to 3/12. This also seems to introduce a break where a leak could occur. 3- that the standing seam should simply be folded and crimped and should not be cut because that could introduce leaks 4- I also heard that it can only be folded and crimped if I go with 26 guage, but that person said I should go with the heavier 24 guage. It makes sense to me to avoid cutting the standing seam. Certainly the idea of having to cut the entire panel and start over when we get to the porch seems unnecessary. I see many standing seam roofs where the panels are not cut where the bend comes for the change in pitch. What I can't see from a distance is exactly how the standing seams are handled, or what the guage of the roofing material is. Please advise me on this. Thanks.
Peter Zimmermann
gullwing

7/9/2007
You don't say what type of standing seam you plan to use. However, I do not know of any standing seam roof that can take the reverse bend required when transitioning from 6:12 to 3:12. The only two ways to do this are to cut the panel ribs and bend the pan (which I would not recommend) or to have two seperate roofs with transition trim under the high roof and on top of the low roof. Your concern about ice dams is valid. I would run a peel and stick memebrane under the lower roof and extend it up under the high roof for about 3'. I would also make sure that my attic was well ventilated, which will help prevent ice dams.
Ken Buchinger
NCI Building Systems, Inc.

7/9/2007
I am considering severl different manufacturers, including Englert and Ryerson. I have Englert on my Vermont summer home and am looking to do something very similar on the new house in Virginia. Your advice seems to agree with my #1 above. The problem is my worry about ice dams. I will note that there are many standing seam roofs here in Vermont which do not follow your advice. It is a single panel from the top of the roof over the house to the overhang over the porch. The roofers here say the best way to handle it is to NOT cut the panel but to bend the standing seam back on itself and then crimp it. I do believe they are using 26 gage rather than 24 gage, though. Also, I note that the school of thought that suggests a separate panel for the lower pitch portion of the roof seems to always refer to a "snap lock" seam, while the "fold it over and crimp it" school says I cannot use a "snap lock" system. I can't separately ventilate my attic because it is a post and beam house with the ceiling open to the rooms below. The ceiling boards are directly attached to SIPS directly under the roof.
Peter Zimmermann
gullwing

7/9/2007
You certainly have a valid ice dam concern. If contractors are reverse bending panels, the seam must not be very tall, it probably is 26 gauge and the metal is probably fairly soft. I would look for a house with a detail similar to yours (that looks good) and ask the homeowner if he has had any problems with it. If not, then I would ask for the name of the contractor that installed the roof.
Ken Buchinger
NCI Building Systems, Inc.

7/9/2007