Retaining Wall Foundation


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Old 04-12-16, 01:35 PM
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Retaining Wall Foundation

I am wondering what type of footing I should put under my cinder block retaining wall. The "soil" behind it is basically solid sandstone, so it doesn't shift much, though I know all soil shifts, especially when wet. I know I need to drain it properly regardless and fill the blocks with cement and vertical rebar.

My question is about the footing: Can I use two or even three courses of concrete-filled cinder block on 6" of a compacted sub-base? Or do I have to pour concrete?
  • Height: 32"
  • Block Size: 8x8x16"
  • Frost line: 18"
 
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Old 04-12-16, 01:39 PM
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Name:  Screen Shot 2016-04-12 at 3.36.37 PM.jpg
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Size:  51.9 KB Here is a photo of the site. Sandstone visible on left.
 
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Old 04-12-16, 01:41 PM
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Solid walls should have a poured concrete footing below the frost line while segmental walls get built on sand/gravel type foundation. Sounds like you're intending the former.
 
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Old 04-12-16, 03:15 PM
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With a block wall you'll also need to waterproof the back side of the block and provide drainage for the water that will collect behind the wall.
 
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Old 04-14-16, 10:14 AM
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As mentioned by previous posters you will definitely need a poured concrete footer, probably even with rebar to support a masonry block wall. It would be much easier to use the stacking blocks designed for retaining walls. They are placed in a compacted gravel bed and then just stack on top of the other. In most circumstances they even hold up better than a conventional cement block wall because they are able to move with changes in conditions instead of cracking. They also don't require the waterproofing on the backside because water can seep through them. If you haven't bought your block yet you deftly should look at this option!
 
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Old 04-21-16, 04:26 PM
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impo, 1 should wtrproof + provide adequate drainage for all retaining walls - even segmented block walls
 
 

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