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TOPIC: Flashing

flashing for a transistion

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What it the proper way to transistion from a 4x12 pitch to a 1 1/2x12 pitch?
Guest User

4/19/2006
I am not sure which is the "upper" roof but regardless the process is similar ... you need to stop and re-start the metal roofing with the appropriate starter method but also with a transition flashing that is under the upper roof panels and over the lower roof panels by typically 6 - 10" each way (usually more under the upper than over the lower) On pitch changes where the lower pitch roof is the lower roof you have to be careful that you do not create a negative pitch on the flashing. This usually involves making sure that the panels on the upper roof do not extend too far downward. Contact the roof manufacturer for additional details.
Todd Miller
Isaiah Industries, Inc.

4/20/2006
I'am doing the same thing. Going from a 6-12 pitch on the upper roof to a 2 1/2 -12 pitch on the lower roof. I don't understand how you put flashing over the lower roof and have it look anyhow. Do you use any seal or sealant to prevent water from backing up in the winter?
Guest User

6/19/2007
It depends so much on the exact profile of metal roof you are installing. If you are installing a standing seam as an example you need to put Z Channel (or similar) between the ribs and seal it in place. The pitch change flashing can actually lock over the top leg of the Z. Always obtain complete instructions from your roofing manufacturer.
Todd Miller
Isaiah Industries, Inc.

6/20/2007
I have a brand new standing seam roof with a change in pitch as described by Dean. It has the Z flashing and self adhesive underlayment, but it leaks. Two areas were identified during an early thaw here in northern Michigan. Not a giant ice dam, maybe just 6 to 8 inches of snow on the lower pitch. The builder and sub just want to caulk the Z flashing and call it good. This doesn't sound good at all to me. It is the underlayment that is supposed to keep the water out isn't it? The metal isn't really intended to be water tight. For the proper fix, do they have to take the metal off and re-do the underlayment? Please help.
Guest User

5/15/2009
The metal is SUPPOSED to be watertight. Your issue is with a flashing not necessarily with the metal panels. When we find problems with transitions on standing seam it is usually that the transition does not extend far enough over the lower roof. Sometimes the sheets on the lower roof do not extend all the way to the pitch break. We call it 'short sheeted'. We are about to replace an entire roof on a really nice cabin because it was done this way by another contractor. [email protected]
Guest User

5/16/2009
The metal is supposed to be watertight, but what about the joints between the upper pitch and the Z flashing, and the lower pitch and the Z flashing. Are these joints supposed to be watertight? If I let them caulk it, is a good test to spray the heck out of it "uphill" with a garden hose? Is there a fix short of redoing that section? Thanks.
Guest User

5/17/2009
Sealants will often be used in those areas but Wade is correct in that most transition problems relate to the placement and style of the transition flashing and often actually creating a negative pitch with the flashings which forces water under the roof system.
Todd Miller
Isaiah Industries, Inc.

5/21/2009
I have the same type roof, going from a 5/12 to about a 4/12. The best I can measure is the pitch is changing about 23 degrees. I am considering to just let the two panels just overlap 5 or 6 inches and use no flashing. Do you think I'm just asking for trouble? This is my shop and the lean-to shelters on each side.
charlie keen

5/27/2009
I would still encourage a flashing.
Todd Miller
Isaiah Industries, Inc.

6/1/2009
Roofers started to install metal roof today. They are not using transition flashing. I have around a 12/12 roof transitioning into a 3/12 roof.This is a log home with a wrap around covered porch. They are extending the upper metal down past the break as an overlap. This is causing an air space between the upper metal and the roof. When they tighten the screws down it is bowing the metal somewhat. It looks good as far as water tight, but I was wondering what long term effects stretching the metal like this will have ?
Guest User

9/6/2010
I have an existing metal roof, ridgeboard to gutter. I want to install a cricket to cover the front porch. The proper way is to cut into the existing roof to flash. I am hesitant to cut into the roof. Is there a metal flashing with adhesive that I can attach directly to the roof which is grand rib three so I do not have to cut the existing roof?
James Dunn

9/7/2010