Gravel or dirt fill behind a retaining wall?


Old 04-28-15, 08:19 AM
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Gravel or dirt fill behind a retaining wall?

We're building a pea gravel patio behind a retaining wall that at its highest point will be about 2.5 feet. Behind the high point there's an area approximately 10x12 that will have to be filled. My question is: cost aside, is it OK to completely fill that area with 3/4 gravel or is there some reason I'm better off filling it mostly with dirt and just putting 6 inches or so of gravel on top of the dirt? Keep in mind the top layer will be 2-3 inches of pea gravel. Thanks.
Old 04-28-15, 09:27 AM
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1. Pea gravel never compacts down or solidifies. You will always have a patio of loose rolly stones that are very unfriendly to chair and table legs.

2. You want a band of clean stone/gravel behind your retaining wall for drainage. Beyond that you can use dirt, mainly because it's usually less expensive than stone but you could use stone. It may work out that getting one big truck of stone is less expensive than two trucks (one for dirt and one for stone).
Old 04-28-15, 03:38 PM
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Some landscape materials supply places have 10 C.Y. trucks with divider beds, meaning they can deliver 2 different materials from just one truck. I had a load of enriched topsoil and loam (5 yards of each) delivered by one such truck a few years ago. Call around in your area to see if such is available there.

For the reasons given earlier, it would be a big mistake to use pea gravel for a patio area. Better to just plant grass or lay sod, if you don't want to use a hard surface material.
Old 04-28-15, 03:45 PM
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.... and you likely need more than just gravel for drainage - where will the water that collects there go? Usually it's beneficial to install a weeping tile to collect and direct the water somewhere else.

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