Any tips for installing downspout drainage piping

Discussion in 'Landscape Architecture and Design' started by GarPA, Sep 22, 2002.

  1. GarPA

    GarPA LawnSite Silver Member
    from PA
    Messages: 2,585

    THis is for a new lawn install...needs to go abou 40 feet..yard has gentle grade away from house. My plan was to hand dig the trench (ground is ez to work)..trying to make a sloping trench to the end. Is there a need to place anything under the plastic pipe? My concern is getting it deep enough to be able to get enough soil on top to grow good grass...have not done one this long b4 so any tips/advice is appreciated....thanks much
  2. Henry

    Henry LawnSite Senior Member
    Messages: 548

    Get your pipe deep enough to keep from hitting it when aerating. 4" below grade should fine but make sure the pipe is able to drain at the end.
  3. Shawn Burns

    Shawn Burns LawnSite Member
    from N.C.
    Messages: 181

    I use a new contraption that looks like a irrigation valve box, only it has a place on the side for a 4" pipe to connect, and the lid is hinged so that it opens when water is coming out. It is buried just like a valve box, so there is no need to taper the pipe or the ditch.
    Your local drainage dealer should have them. Hope this all makes sense!
  4. site

    site LawnSite Member
    Messages: 168

    Aim to bury your 4" sewer and drain pipe at least 1 foot deep to the top of the pipe to prevent frost from pushing pipe out of the ground.
    Make sure there are no kinks or uphill sections and backfill carefully.
  5. GarPA

    GarPA LawnSite Silver Member
    from PA
    Messages: 2,585

    Site...ok 1 foot deep trench...but if I have to run 40 feet, by the time I get to the end in order to have just a little downhill slope that thing is going to be pretty deep and then I'll have this big hole in the yard ..yes that can be contoured and smoothed I guess. Guess what I'm asking is that as long as I dont have any uphill drainage, can I keep the trench at a flat 12"? I know in my yard the builder put them in flat and they work ok....thanks for your good advice...
  6. lawnstudent

    lawnstudent LawnSite Senior Member
    Messages: 472


    when I've installed drains I try to insure that they have at least a quarter inch drop for every foot of run. You want that water to flow away from the house. You don't want the water sitting in those pipes and freezing in winter. Are you sure that your drains at home are level? Did you put a level on those drains and confirm that they are level? A quarter inch fall for every foot may look level, but it is not level. A 40 foot run would require a 10 inch drop. Good luck.

  7. LawnLad

    LawnLad LawnSite Senior Member
    Messages: 738

    1/4" slope will give you pretty fast moving water in the storm pipe. I know a mechanical contractor who installs sewers, etc. and he will run if he has to at no less than 1/8" for storm water and no less than 1/4" for sewage (got to get those solids movin').

    If you had a section of pipe that was level, you might get some water sitting in the pipe when the water isn't flowing, but as long as two pipes on either side were properly sloped you'd be okay. Since water seeks it's own level and you have 4" to play with you could cheat - but it's not ideal.
  8. GroundKprs

    GroundKprs LawnSite Bronze Member
    Messages: 1,969

    Be sure to end pipe in a T fitting. 90% of the lazy landscapers and builders here just use an elbow up to a surface grate, so pipe never drains of water. Who wants a mosquito breeding ground right around the house?

    Proper setup is to dig 1.5 to 2 ft. down from pipe end, and install gravel at bottom of the T. Then when rain is coming down, water flows out the top, but when rain stops, pipe drains out thru the bottom. I wrap gravel in landscape fabric so soil doesn't wash down over time into gravel.
  9. Mow&Snow

    Mow&Snow LawnSite Senior Member
    Messages: 335

    I thought u said that the ground sloped away from the house. If this is the case, digging down 1 foot at the house will be higher than 40 feet down the hill from the house, so you ,might still only be digging 1 foot deep.

    Besides that, with a quarter inch pitch every 10 feet, which is PLENTY of pitch for drain water, you will only have 1 inch of drop over a short forty foot run.

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