Pole barn drainage - need some advice

[DrewStyduhar]

Hello everyone,

I have a 40x50 metal roof pole barn that has gutters and I'm temporarily using corrugated pipe from the downspouts to get water away from the building. Time has come to trench and bury some pipe and was hoping to get an opinion on what to do here. I made a quick pic in paint to show what I'm trying to accomplish. Basically the plan is to dig a ~50 foot long trench 3' from the building and tie the gable downspouts together and daylight everything out behind the building. I also plan to add a trench drain in front of the overhead door openings in the future and want to connect those in with the pipes on each side of the barn. It will look like a big "U". Also, pretty sure the gutters are 5" gutter with 3x4" downspouts.

Some questions:

- What type/size of pipe would you use for orange in pic? Im thinking schedule 40 pvc 4" but im worried the 4" might not be big enough when I add the trench drain. 6"? I also thought about schedule 20 but its possible I might be driving my tractor over where the pipe is buried so sort of nervous about thin wall stuff. Dont want to fool with corruguated stuff for this.

- Should the pvc pipe be solid or perforated? I figured the perf pipe was to deal with wet areas but I'm just trying to dispose of the roof runoff. The barn isnt down in a hole or anything. It is on a grade with the high side in FRONT but its such a mild grade im not real worried about it.

- I was reading where some guys say dont glue the 10' sections of pipe, others say glue it. I planned to glue it (why not?) but figured I would throw that out there.

thanks in advance for any advice or ideas

Drew

 

[jaxs]

I'm sure you will get a bunch of detailed specs based on wigs and wags but here's my thoughts. Use gutter downspouts from gutter to drain line and uv resistant material for above ground fittings. Electrical conduit is suitable for continuos exposure to sun. 4" will carry the load except during floods, fittings and pipe are half the price of 6", easy to find if repairs are needed down the road so 4" it is. To add volocity, I suggest wye fittings rather than tees where downspouts enter lines. If down spouts aren't easy to disconnect,install clean-outs. If alot of leaves and debris fall's on roof,that's your call because there are countless systems,some good,some near worthless.

 

[Spike56]

I have some experience with your project. However, my initial disclaimer is " I am not an expert" .
The first thing that jumped out for me is your question: "Should the pvc pipe be solid or perforated?" I would absolutely NOT use perforated pipe. As the water flows thru, especially when it slows down, it will pull dirt / debris from the holes into the pipe. Add to that, any nearby roots will find a home in the moist soil and grow into the pipe. Bigtime mess / re-work.
Why not glue the pipe ? No idea why anyone would say not to ? Although PVC joints "should" remain connected without glue assuming carefully buried, I would be concerned about the ground shifting / roots - as in old clay tile sewer pipe.
For 40x50 (2000sq/ft) : so round numbers (a 1" rain will be about 1200 gallons). This makes is a little difficult to decide what size and how to construct. Obviously, the rain amount and rate makes a big difference. My only advice is to OVER DO IT. Your drawing has part of the trench and (2) gutters into one pipe. In my opinion, THE thing to be most concerned about is preventing the gutters from overflowing. The weight of the water (unless you have very strong gutters) will bend / deform them. So, If it were me, I would at least use a 4" pipe per gutter.

 

[Dwellonroof]

I've been installing gutter and drainage for over 40 years but in reality you only need a solid 4" and only on one side of the building.

 

[LD1]

The unknown variable in your equation is how much runoff and flow is expected in the trench drain that you want to tie in?

The barn is easy to figure. Because we know its dimensions....and ONLY the rain that falls on said dimension will enter this system. But the trench drain......is it just a low spot draining ~1000 sq ft of surface runoff? Or is this shop at the bottom of a hill and 3 acres worth of water are gonna want to pond there?

Asuming you are accounting for minimal out of the surface drain.....I'd run 4" from the drain, wye in the downspout and keep it at 4 for the width of the building. When you pick up the last downspout, jump to 6.

I also wouldt fool with PVC. I'd do black corrugated. ANd if you are worried about where it daylights and not crushing it, a sitck of corrugated double wall on the ends.

I put in thousands of feet of drainage tile per year. The black corrugated is by far the most cost effective, and at the end of the day it does the same thing. ~$0.40 per ft for 4" and about $1.00 for 6". PVC, even the light weight stuff is 3x the cost

 

[EddieWalker]

Don't worry about Typhoons or extreme weather. You'll never have enough drainage for extreme weather. 4 inch will handle 99 percent of what comes off the roof. Anything else will just overflow your gutters and end up where the rest of the rain is falling on the ground.

In my opinion, corrugated drain pipe is fine for gutters. It's cheap and it lasts forever. I would not worry about the ribs inside the pipe. Water will flow through it just fine.

I've never seen thin wall pipe last. It gets brittle in the ground.

If you want the best, do it like a septic system and use SDR35. Lowes sells 4inch sticks that are 10 feet long for a little over $16 each. Nothing is better for drain lines. But then you will spend a fortune on your corners and T's or Y's. I use Schedule 40 for those with the adapters, which really adds up. But that was for my septic system, not my gutters.

For my own house, I used 4 inch corrugated. It's been 16 years and they are still working great. When I add on next year, I'll stick with 4 inch corrugated pipe for my gutters.

 

[dirttoys]

I wrestle with water everyday. That doesn't make me an expert (in fact if I was better maybe I would fight it less).

Are there any trees, looking at the drawing I don't see where the leaves get picked off?

Best,

ed

 

[DrewStyduhar]

Wow, a ton of info here. I updated the picture to show adjacent trees. There is a pine stand behind the building, maybe 40 feet or so. And there is a white oak about 75 feet from the corner of the building.

I checked the price on 4" vs 6" pipe/fittings and didnt realize the difference was so massive. I plan to make the connection from downspout to wye using a short piece of corrugated so I think it would be easy to snake out if it gets plugged. I havent made up my mind on the gutter guards yet.


I just want to use whatever pipe is best for drainage. I am digging through super compacted sandrock by hand and it's terrible. I dont want to do this again, haha.

The trench drain wont see a lot of water. Its not to drain any sort of wet area.

thanks,

Drew

 

[Dwellonroof]

I sure wouldn't use the corrugated stuff but schedule 35 at the minimum.
You can put a micromesh screen in your gutters to keep from clogging.

 

[Rockbadchild]

I have heard the ripples in corrugated pipe or a culvert for this matter helps clearing and or minimizing sediment accumulation, I have learn at schools that ripples help increasing the flow inside a pipe and at the contradictory I have heard smooth plastic was better to minimize sediment and easier to clean but I am not sure, seen some contractor swearing one and condemning the other and the next one doing the exact opposite … its muddy water id say at best … both have positive and negative guess … if you are going to drive over it I would do rigid if not id do corrugated with the membrane … a nice base of pure stone would help with flow … for pvc glued or not I don't see any advantage personally I leave it up to you but personally wouldn't. … 4 inch should be sufficient especially if you have a couple if inch of pure stone as a base. Screen caps for all daylight ends for sure.