Roof runoff

[Don Phillipson]

Any advice about roof runoff which shoots over eavestroughs?

Problem occurs at two corners of a steeply gabled roof over a deck. Rainfall collects in such volume that at the corners it shoots a foot or more horizontally before falling 18 feet to the deck, where at one corner it damages the stained railings, and at the other has encouraged rot in several siding boards below the deck. We added eavestroughs and a downspout elsewhere, curing a similar problem, but do not know what to do about the corners, where damage now is worse after an unusually rainy summer.

[LouB]

I have noticed vertical metal barriers sticking up a foot or so at those corners on roofs here in Florida, which gets heavy thunderstorms.

Lou

[EXT]

We have shorter ones here up north of the border to deflect the water into the gutters/eaves trough.

[Norminn]

Folks here install a vertical sheet at the corners which directs the water into the gutter.

[Norminn]

Florida here......the thingies are arched and generally about 3 or 4 inches higher than roof surface. That's just a guestimate, but I'm sure they aren't a foot high. Rained here last night and water coming off the side of the roof was no more than about an inch.

[Steve Barker DLT]

You need deflectors on inside corners like that. They will divert the gush sideways right into the gutters. Any decent gutter outfit should have installed them.

s

[Tony Hwang]

Hi, Same here in Alberta.

[Don Phillipson]

But these are outside corners (of the main roof) not inside corners.

[dpb]

Don Phillipson wrote: ...

So you put the splash lips on the outside of the gutters.

A (smaller) set on the inner and some diverters installed higher up to slow the flow rate would also help...

[tnom]

If you have water escaping at outside corners where the roof doesn't funnel the water then the spillage is coming from turbulence. When the water tries to flow around that outside corner it is impeded just enough to overflow.

Install the elevated sidewall and it may contain the water long enough to maintain the desired flow. It may also create a scenario where the inside of the gutter overflows and damages the roof?

[aemeijers]

Nobody else said it, so I will- bigger gutters/downspouts, and maybe a downspout right at the problem corners? If the water comes off the roof in a larger volume than the gutter and downspouts can handle, it has to go somewhere. I have a shallow roof, and if one of the spouts gets even slightly blocked, it shoots over the full gutter in heavy rain. Bigger downspouts, and maybe a couple more of them, are on my 'one of these days' list. No idea why previous owner didn't change them when he replaced gutters themselves, which are shiny and slick rollform, and very easy to keep clean. (I use a leaf blower on them- takes maybe five minutes for entire house.)

I wonder if you could make a water feature out of it- a horizontal pipe to really speed it up, and shoot it into the neighbor's yard? :^/

-- aem sends...

[Steve Barker DLT]

In that case, it needs more downspouts.

s

[plaster]

Water falling 18 feet is enough to crush a person.

You likely destroyed your home. The foundation is likely failing.

Have you ever considered calling a rain gutter company? Rather than spend $1000 on gutters, you have likely caused $50,000 damage to your home.