# Downspout onto Asphalt Shingles?



## 1910NE (Sep 5, 2010)

I recently installed gutters on my place....not to long after putting on a new roof. One thing I noticed with the old roof was that the water coming off the top floor drilled holes into the old roofing material (along the drip line) over time. Now imagine all the water channeled into a downspout, and driving down on the shingles..

Anyway, I added a turn out to the downspouts where the drained onto lower roof lines. I think this will deflect the force of the water hitting the lower roofing, and make it last longer.


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## DexterII (Jul 14, 2010)

I don't know about any specific code violations, but yes, it is a bad idea. I see that you are in Alberta, so you'll have to bear with this dumb American, and redo the math yourself, if you like, but take a 1600 square foor home with, oh, let's say 8 downspouts, as an example. Each inch of rain amounts to approximately 998 gallons, or 124 gallons for each of the 8 downspouts. You can take it from there, to figure your own application, but you get the idea. An inch of rain in an hour is not that terribly uncommon, and you sure as heck wouldn't want to dump roughly 2 gallons of water a minute onto the same 4" by 4" area of your roof for an hour straight.


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## Michael Thomas (Jan 27, 2008)

It's never a good idea to create concentrated runoffs onto composition shingle roofs as given enough time:


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## federer (Aug 20, 2010)

what the gutter guys did for me when i got new gutters was they made a makeshift downspout and connected it to the one from the top roofline to the gutter on the lower roof. maybe i will put a pic up later


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## federer (Aug 20, 2010)




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## FinalSay (Sep 29, 2010)

*No a good idea*



CritterCon said:


> Alberta here....
> 
> I am wondering if there are any rules on letting a downspout from your eavestrough drain onto your shingles, say onto a lower roof?
> 
> I am asking if it is a code violation, or a bad idea in general. Thanks.


Although not against code, it is a very poor practice; as point out by other members it will lead to rapid failure of the shingles. The other problem this may create is moisture entry/damage to the wall that intersects the roof at the discharge area due to the splash/volume of water concentrated in this area.


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## DexterII (Jul 14, 2010)

JWilliams said:


> Dumb American?


Well, I would actually prefer to think not, but was just having some fun at my own expense, in regard to my inability to quickly convert to metric for our friend from north of the border.


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## concretemasonry (Oct 10, 2006)

It does not take too much intelligence to know that water from a downspout will create and ugly looking situation and cause premature aging of the roof surface.

Dick


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