drainage from around a retaining wall

Discussion in 'Landscape Architecture and Design' started by jayman99, Oct 13, 2006.

  1. AztlanLC

    AztlanLC LawnSite Bronze Member
    Posts: 1,035

    This would leave about 3" to 5" of standing water sitting on the trench all the time (depending on type of pipe)
     
  2. jayman99

    jayman99 LawnSite Member
    Posts: 13

    Well guys, a new year is here and my retaining wall problem has not gone away.

    Here is my current thought process....

    I'm thinking about terracing the backyard and replacing the single 7 foot high wall with two walls that are 3 1/2 ft tall each. As I understand, if I can keep the walls at least 7 ft apart, then the lower wall will not have any load from the upper wall.

    I'm not sure what materials to use for the walls. Poured concrete or block walls or cinder block with a stone front. Also, I'm not sure if I need deadman tie backs for such short walls. I have also considered drilling piers under the wall and filling them with concrete to make a bulletproof footer. Is that overkill?

    What costs more...a poured concrete wall or a block wall??

    Thanks!
     
  3. AGLA

    AGLA LawnSite Bronze Member
    Posts: 1,740

    Have you considered having a full basement put under the house with a walkout to a flat yard at the elevation that is around your boat slip? The cost will probably not be too much higher, but the property would be much more usable and you'd have twice the living space (or storage space, if not acceptable by zoning). Room for barbecues, billiards, boats, and sun bathing babes all on one level sounds pretty good to me, ... beats a 15' lawn strip and a 6' wall and a little lawn area around the slip. It will also increase your property value substantially.
     
  4. Mike33

    Mike33 LawnSite Bronze Member
    Posts: 1,649

    I have been told by homeowners that my srw is cheaper than a poured. I do not do concrete work so i can not give a fair opinion on it. Of course i build srw's you know what i would favor.
    Mike
     
  5. jayman99

    jayman99 LawnSite Member
    Posts: 13

    AGLA - I'm not sure, but I don't think a basement is possible.
    The house is built on a slab and so I don't think that will work.

    Mike - what is srw? Stacked rock wall??

    Thanks!

    Jay
     
  6. Fordsuvparts

    Fordsuvparts LawnSite Senior Member
    Posts: 517

    SRW stands for Segmental Retaining Walls.

    I agree with Mike, he know's what he is talking about.

    I don't see a reason to terrace this wall, you will have more useable space if it is just one wall. First thing you need to do is give the water a place to that is not directly undermining your wall any more. Can you get us another picture of the wall from a straight on shot another fron the other side? I can't tell if the large wall is leaning or not but you might be able to salvage the existing wall. Again some more pictures would help a lot.
     
  7. jayman99

    jayman99 LawnSite Member
    Posts: 13

    Hi guys,

    I'm not really too worried about losing grassy area in the backyard.
    In fact, I think the planter formed by the upper wall would look nice.
    In addition, it won't hurt my feelings to cut less grass.

    The main reason I am considering terracing is to reduce the amount of pressure from the soil on the walls. As I have learned, the amount of pressure increases exponentially as the wall gets higher. By having two short walls instead of one 7 foot wall, it should be more stable.

    Although the current wall is not leaning (except on the end), there are several large cracks that probably go all the way thru to the cinder block sub-structure. The current wall is built on a concrete footer that is very substantial. This footer is probably about 18" deep and 18" wide. I would like to re-use the footer as I think it is in good shape.
     
  8. AGLA

    AGLA LawnSite Bronze Member
    Posts: 1,740

    Consider that if you have 15' from the wall to the house and you will put the second wall back 7', you will have a house on a slab just 7' away from the top wall.

    It seems that this entire threads is about how to go about fixing this problem without bringing in an engineer. Yet, every solution seems to have a potential problem that also points to bringing in an engineer.

    It is not as scary as you might think to have a structural engineer work on the problem. If you want to keep the expense down, you can draw out a plan showing where the walls go and how tall they are to be. Then go to the engineer to design the method for it to work.

    In this process, you have moved in the direction of chopping up the water side of your property making it less usable than it is already just to avoid the big scary structural engineer.

    What will the consequences be if the upper tier of your terraced wall muds up and fails seven feet away from a house on a slab?
     
  9. GroundScapesIncorporated

    GroundScapesIncorporated LawnSite Senior Member
    from VA
    Posts: 386

    My suggestion

    Forget about terracing, 2 walls wouldnt be any cheaper or stable than one properly engineered wall. Terracing or stepping up with walls isnt as good as it seems (usually)

    Just tear down the old wall, get a properly engineered SRW installed and sleep good at night.
     
  10. GreenMonster

    GreenMonster LawnSite Silver Member
    from NH
    Posts: 2,702

    Get an engineer, period.
     

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