Downspout emptying onto roof

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Old 08-01-13, 08:27 AM
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Downspout emptying onto roof

I just had gutters installed by a reputable company but am concerned that one of the downspouts on the upper level of a split roof empties onto the lower roof. We have torrential downpours here occasionally and I am concerned that this will ruin my roof. The contractor said this is a perfectly normal installation.

Am I right to be concerned?

Thanks for any advice.
 
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Old 08-01-13, 10:35 AM
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The excess water in that one spot will wear the shingles faster. You could have a splash pan installed there or have the spout run down to the lower gutter. It would have been nice to have the spout installed about five feet to the left and dump right into the lower gutter.
 
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Old 08-01-13, 11:22 AM
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Yeah...not good that its directing a lot of flow right at a roof penetration either. Should be extended down to the lower level as long as that one can handle the increased volume at that point. Could get a lot of splash over if it isn't spread over a larger area.
 
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Old 08-01-13, 03:47 PM
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It absolutely is a common building practice and there should no zoning issues with it, nor is it technically classified as incorrect. However, it is not considered a 'BEST BUILDING PRACTICE'. It is often done this way unless the homeowner specifically requests a different setup because most installers just don't want to be bothered taking a couple extra minutes to put some extra lengths of pipes on there and extend them to the lower gutter. Alot of roofers will tell you it's OK because the water from that downspout is just like all the rest of the rain that's hitting that roof. I've actually seen it in the FAQ on some of their websites. I think whether this will create a problem and how big it will be depends on the house and the install.

If I take a walk around my neighborhood I see about 40% of houses have the pipe all the way to the lower gutter and the other 60 or so have it like in that picture. I have seen ONE home out of all of them that lacked the extensions where the shingles around that upper downspout were a noticeably different shade than the rest of the roof. But it also looked like the angle of installation caused the water to hit the lower roof with some decent velocity. Ideally you want that upper downspout to go all the way to ground level but this isn't practical in every case.

The home I just bought has had a setup like that since the roof was re-done in 2004 with no noticeable problems. That doesn't mean this never causes problems. There are alot of variables: How severe the slope of that upper roof is and how much surface area it has could affect how much force water exits that upper downspout with. Whether it's curved and tweaked so water exiting it flows across the roof pretty smoothly or splashes onto it with some force will also make a difference.

I have also honestly not had a chance to see how the lower gutter systems on the houses with the extended upper downspouts perform when all that water channeled off the upper roof is dumped into the lower gutter all in one concentrated spot.

My setup is somewhat like that except the downspouts transition to the roof rather gradually and only send water across a small corner of it. For now I am leaving it be as I am more concerned with replacing a leaky gutter on the other side of the house. When I shift my attention to the front down the line and replace the sectional gutters out there with seamless ones, I will probably have splash blocks put on the lower roof while they are up there to ensure the water isn't hitting the shingles with too much force. But I don't think I will extend the pipes themselves all the way to the lower gutter. I would be concerned that it might overwhelm the lower gutter.
 

Last edited by eharri3; 08-01-13 at 04:27 PM.
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Old 08-01-13, 04:47 PM
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So, Eharri3, with all the information in your post, can you give one good reason that it is a good idea? I would never, ever, allow a torrent of water to splash across shingles. It may be "common", but as momma said, just because Bubba jumps off a roof, does that mean it is a good idea?? IMO, having the dump further back, atop the lower guttering with a downspout into it, with an angle tail would make better sense, as Dan0661 said.
 
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Old 08-01-13, 05:06 PM
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IMO, it's really no different than the wear that's created on a valley that is closed/woven. Torrents of water run down a closed/woven valley that has shingles instead of metal and that is one of several "standard" installations. Yes,the shingles on a closed/woven valley may eventually wear a little more than other areas, but its normal installation in many places (where metal valleys are not used) and its depicted that way on the wrapper.

It's usually more of an aesthetic issue. If the drop stays where it is currently located, do you really want to see a downspout stretching across the roof? Or if you do what Larry suggested, the gutter would have to get pitched differently so that it drains to the new outlet location. Sometimes gutters don't bend as much as you want them to and it leaves a little standing water in them. That drives mosquito haters and OCD people crazy.

If the company was replacing existing gutters, you can't expect them to change an existing configuration without some discussion first.
 
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Old 08-01-13, 08:10 PM
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I am not saying it is 'good.' I am saying in the best case scenario it can be done in a way that causes such a negligible amount of harm that it doesn't matter. Of course if an installer is taking the easy way out by doing it in the first place the chances are pretty low he will take the time to tweak the elbow, measure the downspout, and test with some water to verify that it doesn't splatter violently down onto the lower roof.
 
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Old 08-01-13, 10:00 PM
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A significant improvement, and costing just a few $$$, would be to install a 90-degree downspout bend on the end of the existing downspout. Doing so would change the direction of concentrated flow, orienting it the way shingles are designed to handle it. Instead of "sideways", which over time is likely to cause water getting under the shingles and into the house.
 
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Old 08-07-13, 03:03 AM
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Thanks everyone for your help

This is a wonderful forum and your comments were very helpful. The gutter man is coming back and adding another downspout. I so appreciate all of you taking time to respond.
 
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Old 07-07-15, 07:22 AM
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I had the same configuration and had a noticeable stain from the shingle rock being worn off. When I had my roof re-done I put a series of elbows and outspots to dump the water into the lower gutter (the garage roof) and a 90 to dump the water into the gutter. No more problems.
 
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Old 07-07-15, 01:34 PM
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Welcome to the forums, Walt. Glad you were able to get your situation handled, and hope the thread helped a little. I'll close the thread since it is obviously aged. People can still access it for information, however.
 
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