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TOPIC: Installation Process

trapezium roof shape... which way to run seams

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Can anyone tell me the correct way to run panels on a shed roof-trapezium shape (24'x40'x36'x34') that has a 3:12 pitch. I am trying to build a new house and have to redo the metal roof because the old contractor installed without vapor barrier. He ran the panels from the 24' side and ended up on the 36' side with metal edges extended out over the side ... not under the rake? edge. I understand why he did this because if he had put the rake edge over the metal the water would have ran under the rake. I know this is confusing ... but can anyone help me here? I have had several contractors look at this and have gotten different answers from each one. The last contractor says to scrap the metal and go with shingles because this shape of roof will never work with metal. Thanks, Mige
Guest User

7/19/2008
Mige, The panels have to be square (perpendicular) with the eave. The rake panels will actually be tapered.
Guest User

7/19/2008
Wade, So how do you square with eaves if one side is lower than the other and not perpendicular to the ground? Will this give the water a direct path to the ground? The 36' side is 1'8" lower and 1' higher than the 24' side. Did you glance at my attachment? Mige
Guest User

7/19/2008
Your attachment doesn't match with what you are telling me. Looking at the attachment it shows: the wider end is higher than the lower end because the shadow line on the wall shows it to be. I also know the wider end from the narrower one because I can see where the rafters kill out at the subfacia, showing it to be tapered on the ends. When we are working on something complex and trying to figure out the most direct path to the ground, we pour water on the deck, it runs directly to the ground and we use that to run our sheets by. We get sheets that have to be cut at an angle on both ends but the seams are straight with the world. Also, I have seen roofs where the contractor just squares with the rake, but this will usually channel the runoff between each panel against the seam. We try to make it where it goes straight down and the panel seams are not diverting the water flow.
Guest User

7/20/2008
Wade, Sorry if I am not making sense but I am at my wits end. You are right... the wide end is the higher end and that is the problem in that the run off does not flow all the way down. It spills off the rake side about 1/2 way down. The way the contractor ran the seams is actually "right with the world" but doesn't work in this case. We flipped the house due to encountering rock and should not have flipped the roof but too late now. So how do I get out of this situation... gutters, high ridge, other seam directions, scrap the metal idea? Thanks so much. Mige
Guest User

7/20/2008
Mige, See the attached drawing. I don't know for sure if it will help, but who knows. I believe you also posted this elsewhere, so a similar drawing is attached. As I mentioned in the other post this might now work for you, depending on the type of metal roofing you have.
Nate Libbey

8/5/2008
Thanks all. Todd Miller
Todd Miller
Isaiah Industries, Inc.

8/9/2008