Steel Roof Leak


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Old 10-17-10, 07:20 PM
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Steel Roof Leak

I have a tiny home with a steep pitch steel roof. This summer I have added a 3 season porch on the front. I matched the steel on the roof. Porch is 9 feet deep and 12 feet long. Put a steel flashing that goes under the house roof 6 inches and over the porch roof 6 inches. The porch roof is a slope roof. If I am saying it right I did 1/12 slope. I was getting a leak on the drip rail of the house roof in my porch. I foamed under the flashing of the porch. Still leaking. So I lifted the house steel and did the tar tape stuff 45 inches wide, one layer across at the top of the flashing onto the shingles that were under the steel and another layer below that under on the flashing to seal it. Still leaking off the drip rail of the house roof. I want to finish up the interior bits and pieces of the porch and do not want to get it wet. Winter is coming. This is frustrating. I am lost and need some direction / suggestions please and thanks.
 
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Old 10-17-10, 08:15 PM
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Well if I understand you right, your problem isn't being helped if you are trying to use spray foam to stop a leak. a 6" flashing that is on a 1:12 pitch is only dropping down 1/2", so that's not much protection against water backing up. It's hard to diagnose a leak sight unseen, but there are 3 possibilities. Water from the upper roof getting behind the flashing... water on the lower roof backing up due to such a low slope... and the seams in the flashing you used between the two roofs. Regarding the last one, one place you could check is where your flashings butt together (overlap actually) in relation to where the leak is. Capillary action can cause water to follow an edge, so when two level flashings are overlapped onto one another they need to be sealed together with sealant to prevent water from wicking off of one and behind the other.

The location of the leak can be masked since it can travel some distance on each layer that it passes through, so don't assume that the roof leak is "exactly" above where the water is dripping. I once found a leak on a screen room that was dripping from the fascia in a 20' wide room. The leak originated outside the room at the seam of two pieces of gutter apron flashing, and then ran downhill inside a piece of fascia cover until it came to a seam where it could leak out. By that time it was over 10 ft away!

Flashings on steel roofs usually are best sealed by using preformed foam closure strip and sealant. This foam closure is made to match the shape and profile of the steel panel. It comes in 2 styles, one that is made to go over the steel roof, and one that is made to go under the steel roof. In your case, on the upper roof, you should have foam closure between your flashing and the bottom of your roof panels. On the lower roof, the flashing should be lapping over the roof panels, and the foam closure would go on top of the steel roof panels and the flashing would lap over the top of it. The edges of the foam closure can be sealed with sealant to ensure that a good watertight seal is being made.
 
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Old 10-18-10, 04:20 AM
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Thanks for the help, I do a lot of projects in my home and most of them turn out great. This is a major project for me, except for the leak, I am very proud of myself. I have great neighbours that help me with the ackward, heavy boards. I think I screwed up on the pitch of the lower roof, I dropped it 14 inches at 9 feet. It is shallow, but should drain?

Questions
The spray foam on the lower roof is not comming out, it is like cement, so what type of sealer should I be putting at the end of it?

I was at the lumber yard and looked for the foam closure and they did not have the profile to match mine, it apparently should have come with the steel. So if I can not locate any, should I shoot spray foam up the top roof and then seal it? and with what? Not sure this is the answer as the leak is under the joiner flashing and if I seal the edge it would still be leaking?

Ok, am lost thanks for the help, more please. :-)
 
 

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