Rain drainage solution

[cubby]

I posted about this an age ago and people asked for pictures. Now that construction is moving forward I finally have some.

Here's my issue. I have a section between two dormers that is essentially marooned from a guttering pov. Look at the pic and it will make sense. Rain falls down that middle section straight in front of the garage and splashes onto/underneath/thru the sides of the doors. I have to do something to keep the rain away from the front of the garage doors. Here are the options I am considering:

1. Running guttering straight down from the middle section to the space between the middle and right garage opening - not very favorable as I think it will look odd with the pipe coming down in the middle of the wall and it will mean having to lose the exterior light in that space (not in the pic but there are lights either side of each garage door)

1. Same as 1 except jog the downspout from the middle section off to the right of the garage doors (where it can probably join one coming down from the right hand section). This too, I think, will be pretty ugly

2. Use a rain diverter to keep as much rain as possible out of the middle section - would have to be high up to channel to the sides of the dormers....would probably only address half or less of the water. Another concern would be it getting ripped off with heavy snows as they slip down in a thaw.

1. Build some form of canopy above the doors to protect them from the rain. This is looking like my favorite option right now, but I'm struggling to think of a good way to do this that will not look odd. The most obvious way I guess is to build an "eyebrow" all the way across with an overhang the same or slightly more than the one above on the main roof, and add guttering. I've googled around but not found many other decent solutions.

Any ideas anyone has will be greatly appreciate. As it is today I get a lot rain splashing into the garage doors and into the garage. I can improve the seals under the doors etc, but I don't think that's ever going to be a proper solution.

TIA

[David Nebenzahl]

On 7/7/2010 3:54 PM cubby spake thus:

The added overhang idea sounds like a good one, provided it's designed to harmonize with the rest of the house on that side. Shouldn't be a huge planning job; do you have an architect? If so, they should be able to quickly knock out some renderings so you can see what it would look like.

That would probably be the best solution, at least drainage-wise. The other ideas of running downspouts from the three sections (you need drainage from all three, not just the middle one) would be less building cost but more downspouts, elbows, etc. But even that shouldn't look that bad, assuming the downspouts are painted the same color as the wall. But the canopy over the doors would look more finished, as if you had designed it in from the get-go.

[The Post Quartermaster]

I have always felt that the simple way is the best way. I'd put a gutter on the facia between the two dormers with downspouts running down the two dividers between the left and center and right and center. See if you can find some plastic gutters and downspouts the same color as the house and after a day or so you'll not even notice them. And neither will anyone else normally.

[Malcolm Hoar]

Kinda crazy but I guess one could install guttering together with a small pump (rather like a bilge pump/sump pump) to shift the water around/over one of the dormers and into a down spout (maybe even on the side of the house).

It would be tricky but not impossible to fabricate something reasonably reliable and with sufficient capacity to handle all but the most torrential rain.

I said it was kinda crazy ;-)

[hrhofmann]

=A0 =A0 =A0 =A0 Gary Player. |

=A0 =A0 =A0 =A0 =A0 =A0|

I think the additional small common roof over all three doors makes the most sense.

If you can project a picture of the house onto some tracing paper, about 11 x 17 or so, you can ink a sketch of the house on the paper. Then using a pencil, you can sketch in various added roof treatments until you get something you like. Much cheaper than an architect for the first, and maybe final go-around. I did this when planning on adding a second garage to our house many years ago, tried about 4 different treatments until we got one my wife and I liked, and then gave that to a builder who got the permits and subcontractors. Turned out great, no one who had not seen the original could tell where we added on until we showed them "before" oictures.

[HeyBub]

I wouldn't worry about it looking odd - the off-center dormers and the structures being taller on the left than the right already do that.

[Ed]

Here is a possible solution. Instead of a gutter, consider a dispersion system to distribute the water over a wider area so it is less likely to splash under your doors. One such product is Rainhandler

I have never used this product but it would seem to help in your situation.

[hrhofmann]

But the water will still all end up outside his garage doors, the OP wants to keep the water away from the garage doors.

[cubby]

Thanks to everyone for the suggestions. As ever, feedback from this group has given me a much clearer view of what I need to do. I plan to go with a small overhang right above the garage doors. Trick will be to get it positioned right and with the right measurements to catch

90% of the rain. Guttering off to the left side will be easy from there.

Much appreciated all.

[Tom Horne]

May I suggest that you may want to run the down piping inside the wall if the interior is not yet finished. If you ran two two inch lines in parallel down to a common line just inside the garage area it could then slope to the left hand corner to be routed into the storm water drain line. If the water is allowed to fall down to the new overhang it is going to splash out into the driveway were it will freeze in the colder nighttime temperatures.

-- Tom Horne

[David Nebenzahl]

On 7/8/2010 6:46 PM Tom Horne spake thus:

When the subject of running downspouts inside walls came up here some time ago, I thought the consensus was that it was a Bad Idea. Pipes leaking inside walls and such.

Anyway, the rooflet can have its own little gutters to keep rain off the driveway. Besides, water's gonna fall on the driveway anyway and freeze. Just less with the rooflet.

[willshak]

cubby wrote the following:

You need some structure over the doors. Not only for the drainage, but for aesthetics. The slab sided house looks like some kind of farm building.

[jamesgangnc]

It doesn't do much for me either. Why are the dormers so short and the small window openings so low in them? I just built a similar garage but detached at our lake house. Can't you raise the window openings?

[mike]

I think Tom is assuming that sewer-grade plumbing would be used, not typical downspout crap. With how easy it is to assemble and glue PVC or ABS, this is a very reasonabe assumption.

[David Nebenzahl]

On 7/9/2010 10:12 AM mike spake thus:

Well, now that you mention it, it does seem OK to do that--after all, other waste pipes go inside walls, so why not storm drains?

Maybe the real problem is the outside connection with the gutter system, although I suppose it should be possible to connect that securely too.

[Larry]

It's done on commercial flat roofs, all the time. There are code requirements to meet. Just punching a hole in a soffit or fascia, to run leaders on the interior, is not a good idea for obvious reasons.

[Nonny]

The water in a sanitary line is typically at room temperature. Water in a similar pipe, used for an in-wall downspout would be at or near the freezing point of water, during most winter snow melts. I suspect that this could cause condensation on the outside of the PVC pipe, leading to mold. The pipe would have to be 3" to fit inside a normal 3-1/2" stud space, also and there would still be little room left for insulation. I also would be concerned about how the part of the line penetrating the roof would be flashed to turn large amounts of running water. It'd be far more than, say, from just raindrops hitting it.

Nonny

[cubby]

It's complicated...the roof trusses are parallel cords as they sit on a knee wall, 24 inches deep on the vertical and the structure above the dormers absorbs a lot of space. We needed the knee wall to be a high as possible to maximise the livable space, but at the same time were constrained by the roof line of the main structure. It was complicated, lots of drawings and renderings, this was the best bet without giving up a lot of interior space.

I do think though that the "rooflet" will make it look more finished. I'm just not sure how big we can go without pillars or some other form of ugly support. Got to discuss with my pros, but if anyone has thoughts, would welcome.

[David Nebenzahl]

On 7/10/2010 7:47 AM cubby spake thus:

I doubt you'd need columns; at most you might need brackets, probably at the ends and the middle between the doors.

An engineer can give you the answer to that question.