downspout drain under paver patio?

Discussion in 'Landscape Architecture and Design' started by Blk94fiveOh, Aug 6, 2004.

  1. Blk94fiveOh

    Blk94fiveOh LawnSite Member
    from MN
    Messages: 112

    I'm in the process of installing a paver patio for a customer. There are 2 downspouts that drain directly to where the patio will be. The customer wants us to install a pcv drain underneath the patio and exit out in the lawn. What would be the correct way to install this? Will the pcv piping hold up to the plate compactor? Do I have to worry about frost heaving? Does anyone have any other tips/ suggestions for this?

  2. capital

    capital LawnSite Member
    Messages: 118

    when a down spot is in the way we tie the drain tile to the downspot and usually use non perforated drain tile vice pvc . If you allow water to run across a paver patio over time u will have some settlement so it is easier to fix the problem ahead of time with tile
  3. stxkyboy

    stxkyboy LawnSite Member
    Messages: 222

    sch 35 grade 6 (the green stuff) PVC
  4. D Felix

    D Felix LawnSite Bronze Member
    Messages: 1,898

    I would use either SDR 35 or Schedule 40 PVC under the pavers. The SDR 35 is the green stuff stxkyboy refers to, it is rated as drain/sewer pipe, and is slightly cheaper than sch 40.

    Once the pipe was past the pavers, depending on where you were going to place the outlet, I would consider adapting the solid PVC to corrogated to finish the run. The reason for that is the corrugated is more flexible and forgiving if the trench isn't absolutely straight.

    Make sure you have fall from the end of the patio to wherever you outlet the drain, you don't want the water to run back and collect on the pavers.

    Ideally, you would want a fair amount of fall from the downspout to the outlet, somewhere in the range of 1/4" to 1/2" of fall per foot of pipe run.

    If there is a ditch nearby that the water could be outletted to, that would be best. Otherwise, if you end the run with corrogated, use a Tuff-tite box (or similiar) at the end of the run to allow the water to outlet from. If the end of the run is with solid PVC, you may be able to use the Tuff-tite, but you can also check into one of those pop-up emitters. I've never used one of those, so I don't know if/how much they might restrict flow.

    Hope it helps.

  5. Russ

    Russ LawnSite Senior Member
    Messages: 540

    Great advice as usual. May I add that your grade away from the house should be 3%. That is adequate for drainage as long it is not disrupted during construction. Where you connect your PVC to the plastic non perf ya will want to stay 3" under the ground to reduce future turf stress. I use the pop ups a lot and prefer them to the grate cap that gets pushed off in heavy rains.
  6. D Felix

    D Felix LawnSite Bronze Member
    Messages: 1,898

    The grates on the Tuff-tites can be screwed down.

    I forgot to add that the easiest way to connect the PVC to the corrogated is to use an internal coupler meant for the corrogated, just break off the tabs on the end that goes into the PVC.....

    Another thing I forgot to add: DO NOT use perforated tile for downspout drains! Perforated tile is only meant for subsurface drainage, not for surface drainage such as downspouts....

  7. blafleur

    blafleur LawnSite Member
    Messages: 229

    I use the pop up emitters on occasion. They work ok here in the south, but I wonder how they would do up in the great white north in winter?

    I havent seen a problem with restriction with them. What they will do is collect sediment, especially sand from asphalt shingles, in the bottom of the elbow that goes up to the emitter. I always tell the homeowner to check this occasionally, of course some wont, and they will have reduced flow or complete blockage after a while.

    As Dan said, an open opening into a ditch or onto pavement is best if possible. If not catch basins or these emitters if they will work in freezing areas.

  8. Blk94fiveOh

    Blk94fiveOh LawnSite Member
    from MN
    Messages: 112

    thanks for the replies.
    what would be the best way to fill in the trench for the pipe that will be under the pavers? Should I just use the fill material that was removed to dig the trench, or should I use the base material (3/4-)? How can I be assured that this will compact completely, and not settle over time?
    How large of piping is nessisary for 2 downspouts? (this is just draining from a 3 season porch, so the roof area is not that large)

    Dan- do you have a picture of a "tuff-tite" box?

    thanks again for all the responces.
  9. D Felix

    D Felix LawnSite Bronze Member
    Messages: 1,898

    Your trench for the drain pipe should be as shallow as possible. The less you dig out the less likely you are to have settling problems later. Backfill with the same gravel you are using for the subbase, and compact it in 2-3" lifts in the trench. Use a sledgehammer to compact it if the trench is too narrow for a tamp.

    Your best bet to acheive as much compaction is to add a little gravel each time (lifts). The less in each lift, the better you will be able to compact it. Like I said before 2-3" is what I would aim for. Also, if there is any way to route the pipe along the edges of the patio, it will make it easier to fix any settling that may occur.

    If you want to make extra sure it's fully settled, do as I suggested above, then fill the trench completely with water to settle the gravel. Do this probably twice, two to three nights/days apart, then let it dry out and continue on with your subbase.

    A 4" pipe should be adequate for 2 downspouts. More than adequate, in fact. Just make sure that the pipe doesn't get clogged with leaves, etc.

    I wish I had a picture of a box, but I don't. They come in all different sizes and shapes; IIRC, our local Home Depot has round Tuff-tites. I think both ADS and NDS has their own variations, Hancor may as well.

    Hope it helps!


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