Retaining Wall Question

Discussion in 'Landscape Architecture and Design' started by UTM-PIKE, Sep 30, 2002.


    UTM-PIKE LawnSite Member
    Posts: 65

    I am doing a retaining wall for a customer that surrounds half of a pool. The wall is 100 ft long with one 90 degree turn, and three foot high, total sq ft is 300 ft. I am probably going to use the medium sized interlocking block (at lowes etc for $2 a block), or should I use the bigger ones (at lowes etc for $5 a block)? I know the bigger ones are more sturdy, but are alot more expensive to use. I was planning on using small gravel (what size?) underneath the blocks, running black perferated pipe inside the first layer of block for water drainage (surrounding it with gravel as well), and lining the entire wall with dupont landscaping fabric. Any problems so far? It will take 900 medium sized blocks, and will probably cost just over $2000 for materials (block, fabric, pipe, gravel). I need help formulating a total cost for the customer. There will also be backfill needed, but no cutting, this will probably be a separate charge from the wall. Are there any formulas for this??? Should I calculate the estimate from the square footage, what are the going rates? Any help is greatly apreciated.
  2. PAPS

    PAPS LawnSite Senior Member
    Posts: 404

    *On a 3 ft wall like the one you decribed... possibly down the line by using the small block, you could have a collapse in the wall. It is recommended by most manufacturers that geogrid is used in applications of 30'' or more in height, for pinless walls systems. if i used a smaller block on that wall i.e Techo-bloc, I would install geogrid behind it and throughly compact. If I used a larger pin system block i.e Versa, then I wouldn't use geogrid.
    * If you havent installed many retaining walls yet, I would suggest a larger pin system block, for it would be easier for you to install and more room for error.
    *Pricing I believe without looking at it obviously would be somewhere on a low end of $6000-7000.00 up to a high end of $11,000-12,000.00.

  3. IBGreen

    IBGreen LawnSite Senior Member
    Posts: 726

    Is there not a wholesale company you can buy them from? We have a block comapny we're lined up with and two nurseries that are able to give them to us for around $1.40 ea. I was just thinking that would give you a larger profit margin.

    Brandon Shaw
    Evergreen Landscaping Concepts

    UTM-PIKE LawnSite Member
    Posts: 65

    Thanks for the replies, I will try to contact a block company and see about getting a discount. What is geo grid? Is it expensive? Is it easy to instal? Is it like a fabric? I have heard about it, but do not know what it is. How does everything else look? Any more input on the smaller or larger block? There is about a $500 difference in the medium vs. the large. How deep should I dig the trench? I was thinking 2-3 inches of small gravel (correct?), and bury the first layer atleast half. Keep it coming guys!
  5. Mow&Snow

    Mow&Snow LawnSite Senior Member
    Posts: 335

    Where to begin?

    As far as pricing goes, I bid everything per sq/ft. For the most part, I normaly use higher end, or atleast fancier, block than the plain walls. These are alittle more but look so muck nicer. I will normally shoot for $40 bucks per foot, which is ALL the money. If that sounds high to them I will downgrade the block and drop the price to 30. I'm not interested in any walls for less than 30 bucks a foot. The work is hard, and there is lots of it. It might seem to make sense to you to lower your price as a first timer. The troublr with this, is that it is going to take you much longer than an experienced guy. so if your making enough money on the job you won't mind spending the time to fix errors that you would other wise leave.

    As for material, I use a very dense stone dust, (not all dust was created equal), that I get from masonary supplier. I buy all my block from them, and they take care of me in discounts, charge account, and speedy free delivery. Well worth cultivating a relationship with a supplier.

  6. paul

    paul Lawnsite Addict
    Posts: 1,625

  7. Mow&Snow

    Mow&Snow LawnSite Senior Member
    Posts: 335

    U had to know someone would pull the seach card sooner or later.....
  8. SCL

    SCL LawnSite Senior Member
    Posts: 543

    The thread paul mentioned is a great opne. Better than most mnfr's tech manuals. You've picked a fairly large project for your first one. Take your time and do it right, my two cents on block are go as big as looks okay as block is dependent on static weight for retention.
  9. paul

    paul Lawnsite Addict
    Posts: 1,625

    Problems down the line...........

    Smaller wall stone from some manufactures are made for walls under 24" tall some are made to go only 16" high, so it would be nice to know what kind of wall system you are using.

    Mow & Snow, I should have understood that there was no way you would have read that thread, It was way too hard for you to fathom :) But some of the newer member here might find that it has a direct bearing on they quality of work that they do. My question to you is what do you call stonedust???
  10. Stonehenge

    Stonehenge LawnSite Bronze Member
    from Midwest
    Posts: 1,277

    Mow and Snow, I don't want you to feel like I'm piling on, but re: the search - if you type everything you posted here 10-15 times, soon you'll want people to refer to an earlier version of the same stuff you typed. For some of us longer in the tooth here, many of these topics have been discussed in great detail. Referring someone to an old thread just gives someone a chance to benefit from those earlier discussions.

    And IMHO, the thread Paul referenced is the best information you'll find on paver and retaining wall base anywhere.

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