gutter leaking during heavy downpour

[mills28]

Had gutter replaced recently and now have a downpipe that backs up slightly and leaks when rain is heavy in light to moderate rain its fine. What to do pipes are 75mm on the whole house. No leaks or issues with the other downpipes.

 

 

[MikeTNZ]

Hi @MitchellMc,

I don't know if I agree with what you're saying, my down-pipes are only held together with two self-tapping screws into the PVC on each side.

However, one thing I did notice from the OP pictures, it seems like there isn't enough fall on the lateral pipes to prevent air-locking when you have heavy rain.

To prevent this, we use 45 degree elbows, not 90 degree elbows, so that the water has better flow and doesn't build up inside the pipe.

Like I said above, there needs to be a decent gap between the end of the down-pipe and the transition that takes the water from the down-pipe, this allows 2 things to happen, it allows air to get up the vertical section of pipe to help it to drain and it also stops leaves and other things blocking the end of the pipe.

[MitchellMc]

Hi @MikeTNZ,

Yes, the downpipe is typically secured to the dropper outlet with screws, as water flows through the dropper outlet into the downpipe. However, the dropper outlet itself, which I am referring to, needs to be sealed to the bottom of the gutter to prevent leakage there.

As shown in the image below, the leak begins just below the dropper outlet. This indicates to me that water is flowing along the gutter and under the dropper outlet rather than falling into it. Typically, to prevent this point from leaking, a bead of gutter silicone is applied around the flange of the dropper outlet, sealing it to the bottom of the gutter, and then it is pop-riveted into place. Without this silicone seal water can bypass the dropper.

There could likely be other issues, but we shouldn't be seeing a leak between the gutter and the dropper outlet like this.

Mitchell

[MikeTNZ]

Hi @MitchellMc,

My apologies, it wasn't intrinsically clear where exactly the spouting/outfall pipe was leaking from with the first pictures.

I'm glad you're on the case!.