retaining wall


  #1  
Old 01-13-05, 05:37 PM
mudslider
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retaining wall

Well the California rains knocked over my old dry stack rock wall. I think it lasted a good 50 years. But its time to build a new one and I was wondering what the difference is between concrete poured masonry blocks and keystone type blocks or plantable keystone type blocks.

The wall is 40 feet long and 7 feet high. Its not near any structure (more than 100 feet away).
Which option is cheaper?
Which will last the longest?
Which can I do in my spare time?

thanks in advance for the help.

mudslider
 
  #2  
Old 01-13-05, 07:15 PM
C
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I think the big difference between a poured concrete wall and any of the dry stack options is that you could construct the dry stack yourself. The dry fit, gravel backfill, and landscape fabric enable you to manage the hydraulic pressure without the engineering needed to design a similar poured wall.

In any model, the cheapest alternative will be the one you don't hire someone to build. The labor component will be significant - either yours or someone else's. I believe that a dry stack, locking wall of most types is simpler to get correct than a masonry wall filled with concrete or formed in place. Many retaining walls on major construction projects have gone over to the dry stack, interlocking blocks. I suspect that the engineers and builders expect them to last a long time.

The dry stack wall you could build as time permits. Concrete block or formed in place will need to be done altogether due to concrete setting limitations.

Hope this helps.
 
  #3  
Old 01-13-05, 08:09 PM
mudslider
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Thanks for the quick reply! Based on reading some installation instructions I think I could handle this. But I was wondering if you still need a permit and an engineer?

If I did it over time should I build one course at a time or a complete 7 foot tall section at a time?

thanks again. I think I got more help from you than from all the contractors combined.

mudslider
 
  #4  
Old 01-14-05, 10:34 AM
vernonthomas
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Good Drainage and Compacted

Hi there.

If you are going to build with the keystones, make sure you put in good drainage and make sure when you backfill each course you compact it. The keystones from many companies often have a lip on the back of them that offsets the courses which makes it more stable. Usually any wall over 4 feet needs to be secured. There is a product out there that is a roll of mesh that is 4 feet wide and is put over the 4 foot high course and behind it. You then backfill over that. It acts as a deadman. You use it every other course above the 4 foot height.

At the bottom and behind the first course you should run a 4" piece of perferated PVC (drain pipe) the whole length for drainage. Cover this with gravel and cover the gravel with landscape fabric and then backfill. The landscape fabric acts as a barrier for the dirt so it will not clog the drain pipe.
You could also add some weep holes if you wanted.

Hope this helps.

Vernon
 
  #5  
Old 01-14-05, 07:25 PM
C
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I would direct you to your municipality or county building code enforcement department for an answer on the question of needing a permit to build this wall. It would be better, in my mind, to have the permit you need than to pay the fine or other eventual expense otherwise.

Building the dry stack, interlocking wall is pretty straightforward from the instructions and guides that appear for these products. I doubt that engineering would be needed to use them. The formed-in-place or filled concrete block walls would be different because of the nature of the construction.

Hope this helps.
 
  #6  
Old 01-29-05, 09:36 PM
mudslider
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95% Standard Proctor?

speaking of instructions...How do I compact to 95% Standard Proctor? Is there a way I can tell what density I have achieved?

thanks again
Mudslider
 
 

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