When it rains, water from the second floor downspout misses the first floor gutter on the right side and comes down the siding (as shown below). You can see the evidence (vegetation) growing to the side of the lower gutter. What is the best way to fix this? enter image description here

  • 1
    Gutters can often slide a little bit if attached with brackets/holders instead of being screwed in. If yours can scoot, tap the front side of your porch gutter so as to drive it back toward the house, right up against the siding, so that water can't sneak behind the gutter end cap. I would also apply paraffin, rain-x, or just rub a candle in a swath on the porch shingles away from the roof, to guide the water away from the siding, you might be surprised how effective this is.
    – dandavis
    Commented Feb 20, 2023 at 22:29
  • I would also caulk under that angled edge (corner) piece, water is getting under there well before it gets to the end by the lower gutter...
    – dandavis
    Commented Feb 20, 2023 at 22:42
  • 4
    Good grief Charley Brown, I have a couple of 2nd story downspouts draining onto the first story roof. I simply extended the 2nd story drain spouts to reach the lower gutter and put a 90 elbow at the end to ensure it went into the gutter. Just a few bucks and problem solved. Commented Feb 20, 2023 at 23:59
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    Just attach a 45 deg elbow to the existing end to discharge the water 8" or so away from the wall. George Anderson's answer is OK, but I don't think you need to go that far.
    – SteveSh
    Commented Feb 21, 2023 at 2:16

7 Answers 7


In my area (Ohio), companies extend the downspout horizontally down the roof and INTO the lower gutter. They claim it reduces erosion of the shingles but also prevent said issue from happening at the lower gutter.

  • 1
    You might want/need to go to a bigger lower downspout if you combine them, in which case you can use the old one above the porch...
    – dandavis
    Commented Feb 22, 2023 at 0:11
  • Having this issue, too, @dandavis: the water from the main roof coming down onto the porch roof in addition to the water off the porch roof is just overwhelming the porch's gutter/downspout. I'm going to run separate downspouts as my choice of option. (I don't have them both right there in the same spot, so it won't look as odd for me.)
    – FreeMan
    Commented Feb 22, 2023 at 16:53

I expect to get a lot of flack for this answer, but here goes.

Remove the 2nd floor gutter.

Often gutters can cause damage to the roof deck, soffiting and facia from rain water that gets backed up and seeps into the wood.
( if your structures are not wood, great, nevermind)

2nd floor gutters are difficult and dangerous to clean. As a result the damage mentioned above occurs.

Finally , If you must keep them, try getting an elbow that send the water out of the downspout 90 degrees to the left of what you have. The rain then will disperse across the roof before entering the lower gutter.

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    I would rather the facia get damaged than the foundation. Generally, if you know something is bad you're not supposed to say it aloud...
    – dandavis
    Commented Feb 20, 2023 at 22:27
  • rain running off a roof can be delt with by having gravel, or riverrock planting beds and bushes that help scatter the water. (damn, I knew this was coming.)
    – RMDman
    Commented Feb 20, 2023 at 22:36
  • wouldn't gravel or round rocks prevent run-off and guide the water down though the topsoil right up in the foundation's business? Plants don't drink very much when it's cold, and it's late-fall/early-spring rain that freeze and clefts that's the main source of damage. The best bet is to get the water away from the house as much as possible.
    – dandavis
    Commented Feb 20, 2023 at 22:40
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    Unless you have downspouts that carry that water 3 feet or more away from the building, you are kidding yourself that the water doesn't leach to the foundation.
    – RMDman
    Commented Feb 20, 2023 at 22:44
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    Remember that rain , when viewed out of a downspout, looks like a great amount. However that is the collection of rain that has fallen over a generous roof and collected into a much smaller point. In most cases the roof makes rain run off, as it was designed to do. The resultant rain waters our plants. People have been indoctrinated to believe gutters must be installed to prevent this.
    – RMDman
    Commented Feb 20, 2023 at 22:53

Depending on the roof area that the upper one is draining, you may have to run that downspout all the way to the ground, rather than dumping it on the lower roof.

You can try just redirecting it out onto the roof, rather than running along the wall, so it can spread out and slow down a bit before hitting the lower gutter. It might not work, or it might.

  • How should it "redirect"? A vertical elbow (turned horizontal)?
    – dandavis
    Commented Feb 20, 2023 at 22:25
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    Looks like an "A to B transition elbow" would do the job best, spreading the water out more before it hits the lower roof.
    – Ecnerwal
    Commented Feb 20, 2023 at 22:38

When my house was re-roofed a few years back the roofers solved this exact type of issue by installing a water flow diverter flashing just above the rain gutter.

I have made a crude picture of how that may be applied to your roof area.

enter image description here

To be properly installed the flashing needs to extend up under the shingle runs above the exposed part. It also needs to be extended up the side wall behind the siding. In your case the J channel where your siding terminates along the roof edge makes the installation of the diverter flashing a bit tricky.

The diverter flashing on my roof was somewhat simpler because it is just behind the siding which is cedar on my house without a J Channel like yours. If I recall the piece was made of galvanized sheet metal that was soldered where it folded back on itself and then spray painted to a color that closely matched the roofing materials.

  • @ Michael Karas, That "diverter" will cause more damage to your roof and siding, than a flock of woodpeckers. It essentially is damming water on your roof. A slight, otherwise insignificant, opening will now be susceptible to rain water that would have run off the roof. If you Absolutly have 100% sealed coverage , ok...if not...oh well, you will find out in time.
    – RMDman
    Commented Feb 20, 2023 at 23:23
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    @RMDman - If you are going by my halfa$$ed picture then please calm down. You are 159% wrong about how such diverter is installed on my house. If it wasn't raining outside and I already had a ladder out I would climb up there and show a real picture. The actual diverter is NOT a right angle bend parallel to the edge of the roof. It is instead only a small angle to steer the water down flow all of about 1/2" to 3/4" over from the siding.
    – Michael Karas
    Commented Feb 21, 2023 at 4:07
  • This was my first thought as well. You can see an better example of what he's talking about here.
    – bta
    Commented Feb 21, 2023 at 21:57

The elbow on the top downspout that turns out onto the roof is called a be elbow, you need an a elbow so that the water kicks out under the roof more and fans out as it trickles down. And then you would put a diverter where the water is coming off your shingles right now, I think I saw a picture of what it looks like drawn in one of the last comments. It's just a piece of metal cut and angled toward the length of the gutter to help divert the water away from that endcap. Changing the elbow out will pretty much take care of it waterworks of centripetal force and waters is static it sticks together and forms of shading action what goes over pause the rest over with it as seen in the leaf guard commercials with the rounded cover.


Extend and/or move the second floor downspout so that it does not feed onto the first floor roof This may require re-hanging the second floor gutter to be low in a different spot.

At a minimum extend it across to the first floor downspout, and either discharge into the first floor gutter or into the side of the first floor downpipe.

Draining a gutter onto a roof is really only acceptable when the top gutter only catches a small amount of rain (eg: dormer windows), and even then a spreader pipe should be used so that the flow from the gutter does not cause excessive erosion

  • This is the most work, but achieves the best result. Concur.
    – Criggie
    Commented Feb 21, 2023 at 22:46

This is quite common down-under.

Perforated Pipe

From Attainable Sustenable

This one has been hand drilled but apparently one can purchase "Multi-hole perforated PVC pipe" for drainage. But you really need larger holes.

enter image description here

From PVC Plastic Perforated Pipe

The way its used is to glue a section at right angle (with no cap) or at an acute angle with a cap at the end. The water is then spread across the roof.

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