After a new roof was put on my house recently, one of my downspouts ended up completely clogged. Based on my attempts to unclog it (I have done this many times in the past at multiple paces on house when leaves, twigs, whatever occasionally block a downspout) my educated guess is that a chunk of the foam padding the roofers use for protection from the shingles as they are working ended up in it. So typical poking, prodding, or heavy jet of water won't work; in fact I suspect I made situation worse by using these typical approaches before understanding the nature of the blockage.

The gutter is riveted on and painted tight so I cannot disassemble without destroying it. I might/could be able to snake up from bottom, but don't really have faith that would work given the vertical rise and two ~90 angles involved. If there was a way to work an articulating "clawing" device in from top entry hole I could start picking away at the blockage from above by pulling material back up and out, but I am not aware of any tool heavy-duty enough as well as having the 90 degree flex necessary. I guess I could wait for it to get dry and pour some gasoline down and light it...lol. j/k.

But seriously...any thoughts or suggestions?

  • 2
    Those rivets are pop rivets and a drill removes them quite easily without damage.
    – crip659
    Sep 19, 2023 at 21:21
  • 1
    I find that using an air rake/leaf blower on the downspout lifts clogs up and out against the direction in which they got jammed. Once I had to duct-tape the spout and blower port together, but it made it rain down a ton of detritus. For organic clogs, try pouring a can of coke down the gutter; it will dissolve some of the non-organic solids and feed decomposers that will eat the clog, letting it pop free within a week or so.
    – dandavis
    Sep 19, 2023 at 21:22
  • @dandavis: you mean use leaf blower at bottom to push stuff out the top, right? I'll try anyway, but as mentioned this is not your typical leaf-n-twig clog.
    – AA040371
    Sep 19, 2023 at 21:26
  • @crip659: Thanks, I didn't realize that so I'll keep in mind, but for a few reasons this would really be a last resort option for me. I am really hoping for something more "plug-n-play" :--)
    – AA040371
    Sep 19, 2023 at 21:29
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    Cheap video endoscopes are available online in lengths of at least 15 feet or so; I would get one to feed it in both ends and figure out exactly what the issue is. It's a fun tool to have afterwards, too.
    – Armand
    Sep 19, 2023 at 22:03

1 Answer 1


If it is not your typical leaf-n-twig clog, as you suspect.

Stronger methods are needed to unclog it.

Depending on the length get a 10, 20, or 30 foot drain snake and clear the clog

  • A nice feature of a drain snake, as opposed to something comparable like a fish tape, is that the snake has a "screw" at its tip which can be wound into the obstructing object.
    – Greg Hill
    Sep 20, 2023 at 3:01
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    But using a fish tape (or other flexible long item) would be good to try and narrow down where the blockage is to better know whether it's better to come at it from the top or bottom with a drain snake. Or, if it's really blocked and holding water well, fill it with water and tap on the downspout with your knuckles to identify by sound where it's water-filled vs empty.
    – Milwrdfan
    Sep 20, 2023 at 4:09

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