Underground Eave Downspout Drainage

[Hysyde]

I recently built a couple of out buildings and am looking at digging up the grass and extending the gravel driveway to them (shaded in blue/green in picture).

These buildings are at a slightly lower grade than the house (hard to see on the picture) and a lot of water tends to head in that direction, partly because the eaves trough dumps that way. This winter, with the freeze/thaw cycles we had, the ice almost built up the level of slab in the bigger building. I wasn't too worried, and I manage the water by chipping and craving rotues out for it, but I'm looking for a way to divert the water further away from the house, and preferably not right in front of these out buildings.


Because there is no real ditch within a reasonable distance to divert this water, I'll simply be taking it to the lower grade areas behind these buildings (probably a few feet lower than the house). This means the drains won't have any frost protection and are pretty much guaranteed to freeze in the winter. There won't be a ton of slope either. I can live with that, but I'm hoping for spring/summer/fall water diversion.

I'm thinking of putting in some small catch basins (circles in picture) and running corrugated 4" black agricultural tubing (red line in picture) with it exiting to the surface somewhere behind the buildings. I might possibly move the catch basins to right under the downspouts so I don't have the extensions always out in the way on the walkway. So basically the downspouts would dump into the catch basins unti lthey freeze, and then the water would just flow on top of the grade/percolate in as it does now.


Would this work, or would it simply break up the first time it freezes? What other strategies could I use to get water away from the house and preferably not into the area in front of these buildings?

I'm hoping to put in the gravel in the next month or two, and would obviously like to put pipe in the ground at the same time (if I go that route).

Thanks for any tips/help

 

[Ford850]

Why not bury 4" pvc drain tile with slight grade to where you plan to discharge? I've always put in vertical pvc, starting below each downspout and capped with a downspout fitting. Then down a foot or three, with a elbow to your horizontal run. You don't need much drop to keep the tile open in the winter.

 

[4570Man]

I don’t live in a freeze prone area but I have 2 gutters dumping into a buried 55 gallon barrel with holes drilled in it and it works flawlessly.

 

[Hysyde]

Why not bury 4" pvc drain tile with slight grade to where you plan to discharge? I've always put in vertical pvc, starting below each downspout and capped with a downspout fitting. Then down a foot or three, with a elbow to your horizontal run. You don't need much drop to keep the tile open in the winter.

PVC costs significantly more (over 3 x as much). Not that'd break the bank or anything, but I figured ag tubing would be much less susceptible to cracking from freezing. I'm also reluctant to tie directly in off the downspout as I want to be able to bypass if required.

I know plenty of setups like your talking about that do work fine, but I've seen others that don't. I won't have much slope. but I should verify what it will be before I do anything I suppose. Heck, one of my completely vertical downspouts will even freeze up from time due to it not getting any sun, but the black roof getting plenty.

 

[Hysyde]

I don’t live in a freeze prone area but I have 2 gutters dumping into a buried 55 gallon barrel with holes drilled in it and it works flawlessly.

Dry wells like that seem to freeze here mostly from what I've.

It wouldn't be an option with my high water table anyway (I hit water at 3.5/4 feet when I dig in posts), plus I want to move the water further away from the house. Those to downspouts in the picture take a good chunk of water off the roof, and in the spring when my water management is the most critical, there's always 2 to 3 feet of melting snow they're dealing with.

 

[ray66v]

Keep in mind, flowing water does not freeze. Only stagnant, or very slow flowing water can freeze. If your drains are installed properly, they should not have any standing water in them, so you do not need to worry about them freezing.

My downspout drains are around 1' below the surface, and run over 150' long to the covered ditch at the street. They never freeze.

When running drains to daylight, under the right conditions, some ice can accumulate where the water exits the pipe. Ideally, you have enough fall at the exit point to keep any ice that accumulates from completely blocking the exit. Keep in mind if it rains, flowing water will melt ice in, or near the end of the pipe, as long as there is some flow.

If you feel there will be an issue, you can put at least one alternate exit point, such as a "T" facing up with no pipe in it, near the end of the drain pipe to allow water an alternate exit. You can also put a vertical "T" where you downspouts enter the pvc, as an alternate exit.

 

[Snobdds]

You're going to need a cleanout a few feet before the tee where the two pipes meet. Any blockage there and you've rendered your drainage system useless. I don't see any problem in the way you have it laid out. Just make sure you size the pipe big enough to meet your flow requirements, also use a Schedule 80 pipe since your going under a driveway.. Then just make sure you have adequate slope in the pipe. If all done right, I would never worry about it freezing.

 

[Hysyde]

Thanks for the advice.

I'll go PVC then and see if I can find any schedule 80.

As for adequate slope; would that be the same as your standard indoor drainage slope (1/4" a foot min.)?

 

[4570Man]

Why do you need schedule 80? It’s probably $5 a foot for 4” and unnecessary for normal use. I’ve drove plenty of heavy traffic over schedule 20 4” pipe with minimal ground cover. The heavier schedule 35 green drain pipe would be adequate for anything.

 

[Hysyde]

Why do you need schedule 80? It’s probably $5 a foot for 4” and unnecessary for normal use. I’ve drove plenty of heavy traffic over schedule 20 4” pipe with minimal ground cover. The heavier schedule 35 green drain pipe would be adequate for anything.

I was thinking that might be overkill, and not something I can just pick up at Home Depot either.