Rain water defelecter to clip to guttering?

get a deep flow ....

Doesn't make that much difference when it's 'issing it down and the water is simply overshooting the gutter, rather than the gutter being full.

If it did it during normal rain I'd do something about it but otherwise not.

I have a high level downspout that discharges onto a low level roof and in heavy rain, that did overshoot the low level gutter and end up running down the wall.

I took a 2' offcut of gutter and cut it lengthwise along the middle forming two quarter rounds. One I glued as an upstand to the inside surface of the outer edge of the existing guttering (using PVC solvent weld) with the top edge curved towards the roof, and the other piece is resting under the tile edge and felt curving down into the gutter (acting like a felt support tray - I'll remove it when I get around to fitting proper felt support trays along that roofline).

That has worked well for ~30 years now.

This solution was for just a short section of the gutter. If you have water overshooting for much of the length, then the gutter is probably positioned wrongly with respect to the tile edge.

In message , Dave Liquorice writes

Here we have a large flat roof with reverse fall butting onto the main roof. Between the two there is a long narrow "gully". At its end it has a sharp turn formed to send water down a narrow piece of roof into the main guttering.

It's OK in normal rain. In storms it spouts water about 3 feet straight out into the garden.

I've followed Dave's "otherwise" option, as I don't think anything else would be better, short of redesigning the whole roof.

Sounds like a plan.

The overshoot is just for the short length below the downspout from the main roof, and only in severe weather.

Cheers

Dave R