How to divert water from small awning roof
bongo30
| Posted in General Questions on
Hello, we are starting to install gutters on our new construction home. We have a small portico roof/awning roof on the back that doesn’t have any columns to hide the gutters. Are there any way to divert water from that roof? The contractor proposed chain links as indicated by green lines in the photo (we are not a big fan) or in ground grate/gutter that connects to the rest of the drainage (blue line in the photo) but will that be enough? Any other solutions?
Thank you!
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Rain chains look good on some styles of home and seem to work pretty well. I think they are most appropriate on Asian-inspired architecture such as Craftsman-style homes.
Is there a reason you can't add columns to attach downspouts?
You might consider doing a rooftop rain diverter instead of a gutter. The best I've seen, by far, are made by my friend Ray: https://v11raindiverter.com/. Their shape prevents stormwater from spilling over the top, which is a problem on other styles of rain diverter.
Thanks for posting that link, those diverters are perfect for my house.
We can’t attach the columns as the awning is pretty small, about 3’ approximately, so the columns would overwhelm the space. I will take a look at the diverged you mentioned but would the water still come down at the sides? Thank you.
Yes the water would spill off the end of the diverter, so you would want an area of largish-diameter stone (3-4") on the ground for it to land on. Rain chains usually have something similar, with a catchbasin or other system below. Here's an article I wrote a long time ago about one way to deal with this sort of thing: https://www.greenbuildingadvisor.com/article/ground-gutters.
The simplest is standard gutter (or custom bent if you don't want it bulky) with the downspout running almost 90 deg back to the house then down. For a small roof like that 2" downspout should be enough so it won't that visible.
If you do the custom route, the 2" wide gutter can be integrated into the facia so it won't be visible at all.
Forgot to mention also, but we have large pendants on each side of that sliding door so we’re afraid that if we do the typical downspout route it would run down next to the pendant and won’t look good. Any other way to hide it when running it down?
Thank you!
I guess you can always use thicker rain screen strapping and run the downspout under the siding or box around it with some trim and install the lights over it. Lot of it depends on the design and what looks the best.
If you do run the downspout under the siding a bit of extra peel and stick there is good insurance.
For such a small roof the diverter Michael suggested seems like the simplest option. You'll still get some splash back but looks to be far enough from the house and not a big roof area.
Maybe you can take a page from the commercial book, and use PVC pipe as a "downspout", then hide it in a false column or wall detail made from trim board material? Using real pipe has the advantage of being able to be solvent welded together, so you don't have to worry about potential leaks at the fittings the way regular gutter/downspout materials can. With that small awning, you should have minimal amounts of water to deal with, so you could probably get by with a small pipe like 1.5" or maybe even 1.25". You can use a reducer fitting "backwards" to act like a funnel to get that small(ish) pipe to connect to a standard gutter at the eave, or possibly use a bulkhead fitting to tie the pipe directly into the bottom of a section of gutter and use a 90 fitting as Akos' suggested to go straight back to the wall. With sealed fittings, it doesn't matter if everything slopes because pooling water won't leak out.
Bill
In the aftermath of the widespread failure of building envelopes in BC commonly called the Condo Crisis, I attended a CMHC seminar to look at the causes. One of the ones they highlighted was the practice of boxing in downspouts, or bringing them into the wall assembly. I'd caution against that as the consequences of failure are too high.
I was involved in a major renovation on Nantucket when a boxed PVC downspout froze and flooded the balcony deck it drained, which then flooded the house. Good times.
Michael,
That might give Martin some ideas for his Christmas poem this year.
"There was a deck builder in Nantucket, whose drain blocked and ....
LOL!
There was a deck builder in Nantucket
Whose drain blocked and house got flooded
Hidden downspouts seemed so nice
But were no match for northern ice
I've seen a nice way to implement this was on a residential mid rise. There was a U shaped channel for the downspout in the wall that looked to be formed by a structural I beam and the downspout ran through that. The downspout was flush to the siding and a rectangular section that was color matched to the siding so it was barely noticeable almost like a piece of trim. Since the downspout was still technically outside the building envelope and only boxed in on 3 sides, I think it avoid the issues with having it buried. Any leaks would be pretty easily visible.
As with any detail like this, I'm sure it wasn't cheap.