inside corners on guttere overflowing

Old 07-19-10, 06:44 PM
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inside corners on guttere overflowing

Hi all,
We have new gutters-aluminum, and they work well with one exception: in a heavy rain, each of the 2 "inside corners" cannot handle the extra volume of water created from the roof valley that empties into it.[A portion of the roof line was changed, creating the valleys, so this is a new problem.]
I have seen what looks like vertical extensions on the outside of the corner in other houses, but I can't find them in stores, and I'm not sure how well they work.Anyone familiar with these?
Also have the aluminum "leaf guards" installed on the gutters- the "wide mesh type (as opposed to the solid surface-tension type). Would removing a few inches of the leaf guards at the inside corners help with the overflow situation?

Thanks in advance for your help.
Old 07-21-10, 06:25 PM
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First check the pitch from the inside corners towards the downspout. The next time it happens, notice if the water out of the downspout is at full force. In other words, is the entire pipe being used?
Old 07-21-10, 09:44 PM
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What you have seen is generically known as a "diverter flashing", and at residential jobs it is usually field-fabricated as required.

The issue here is that if the gutters cannot accommodate the runoff from the valley, and the water backs up behind the diverter, it can work its way back up under the valley flashing and rot the sheathing, or behind the gutter and rot the fascia and soffit (and perhaps cause water intrusion at the interior), or both.

So depending on the intensity of the run-off from the valley you may need for someone to fabricate a diverter flashing, or a diverter plus a flashing from from the valley to the lip of the gutter, or such a flashing plus a triangular conductor head feeding a downspout below which is dedicated to receiving the valley's runoff.

The result may not be "pretty", but I make a good part of my living investigating why "pretty" sometimes just does not do the job - even at residential properties -when the job is controlling water flow.
Old 07-23-10, 03:31 PM
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Check if you have tall trees around the house. Sometimes, you have rotten leaves clogged there.
I would say so especially when you did NOT have the issue right after the installation.

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