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Valley flashing at dormer
I'm looking for some input on this problem. When the valley flashing ends upon transition from the dormer to the main roof there is a ridge obstructing the waters flow. I can see a huge potential leak there and next to the eave purlin. Please see the attached pictures to clarify my problem.
Yes you will have a problem. The valley flashing should transition out on the lower roof sheet which should be in tow pcs. The first from the eave up to the top of the valley metal and the second over the valley metal terminating in line with the other sheets.
I plan on doing a roof in the spring and have dormers that will require the same transition. Your answer to Ghost Rider makse sense, however. Would you anticipate a small "lump" in the roofing due to the upper and lower sections of the metal not mateing properly/completely; due to the upper piece partially laying on the flashing? And or wouldn't the valley skew uphill because it is resting on the lower piece of metal(this strikes me when looking at Ghost Riders attached picture and envisioning the valley passing over the first rib of metal that would otherwise be the lower piece)?
It depends on the profile and the degree of experience. Layout of the sheets is key and the bolder and busier the profile, the more difficult it is. If you choose a profile with a 12" flat, it is not too bad. You can flatten the lower sheet a little for the transition and try to get the valley centre to end just before a rib on the lower sheet, then form the upper valley tail over the rib.
Hi Allan,
I'm trying to solve some leaks in my brand-new standing seam metal roof where the dormer valley flashing meets the roof (inexperienced installer, but that's another story). Intuitively, your suggestion to overlap the section of roofing where the valley flashing drains onto the roof makes complete sense and I'm tending toward having it re-done that way. On a recent trip to Colorado I noticed that the common technique there is to cut a slit in the section of roof and feed the valley flashing through it. The valley flashing then continued three inches or so out over the roof section. That approach still leaves you with an exposed join where caulking would appear to be the only thing keeping water out. I assume you've seen this technique; is there something under the covers that makes this approach water tight?

Our home is in rural Newfoundland, Canada where no experienced installers were available. I've attached a photo.
David Mosher
Attachments: View Attachment
Hi David,

I live in an A frame cottage in Northern Ontario and I am planing to open p the kitchen a bit with a dormer. I have metal sheeting similar to yours.

I was wondering what to do about the flashing in the valleys created by the dormer and the main roof. Obviously they tuck under the existing roof and the dormer roof, but what happens at the peek. Is there some method of getting the flashing fixed so that this doen't leak. My only though is to simply use a lot of calking (possibly silicone) at this spot.
The ridge flashing on the dormer covers the end of the valleys at the peak and tucks under the main roof. Cut it about 6" long and it will have to be cut in the bend from where it comes into contact with the main roof (the extra 6"). This spreads out and leaves a gap, simply cut another piece of metal and put down your sealant and cover the gap.
You can make it look nice and neat, no leaks, no gaps. Also, don't use silicone, use butyl.
it sure would be nice if we could see some really good pictures or the area where the dormer valley lands on the roof.. there are no details available anywhere for this...why?
Hawkes Not sure why but it does take a little time and a bit of a craftsman .
We just did a 35 sq new build with 4 dormers with valleys in the center of the roof. a garage with a ridge oppisite the house and a breezeway. o ya and a 4/12 to a 10/12 transition from the porch to the house. once you see how its done it makes sense. cutting your cap and then caulking pieces to it doesnt sound quite right. the way we install our valley is actually water tight without the cap over top but we do but it into the roof just as added protection. I could probably get you pics or I can email you my phone number.
here are the photos taken today.a little icy
Attachments: View Attachment
heres the big picture
Attachments: View Attachment
all edges hemmed and under lapped
Attachments: View Attachment
sidewall, under soffit up the fascia and under valley
Attachments: View Attachment
Thanks. Looks very good.
to dlc, or anyone who can help:
I need pictures and information about how to install valleys for my dormers. I am using sheet metal and I need to know how to flash it. Thank you, please reply.
sorry for the delay. I can give more pics on standing seam or the ag panel. I can also call you and discuss it over the phone. E mail your phone to dom@allmetalworksinc.com Thanks
Am about to do a job and have struggled with this properly for quite some time when Ideal came up with a new product......


see item #1
Can you offer any help for a corrugated roof at the dormer roof junction. It gets more difficult. It's a P7 pattern if that helps.
Hi, Did you manage to find any details of the valley flashing termination?


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