How to Level the Gravel Base for a Block Retaining Wall

Leveling blocks for a retaining wall on a gravel base

I’m having a hard time leveling the first row of blocks on the base layer of gravel on my retaining wall. One piece of gravel can throw the blocks off. Can I use sand instead of gravel to level the blocks? -Kevin

To keep the blocks on your retaining wall level and structurally sound, you need a base layer of several inches of well compacted, sharp gravel. A handheld tamping tool can really help in getting the gravel level, but you’re right – one stray stone can throw off the entire operation!

Some block manufacturers recommend spreading a 1/2″ to 1” layer of sand on top of the gravel layer, to help with leveling. Be sure to use coarse builder’s sand, and tamp it down firmly to keep the sand from shifting and settling after the wall is built.

If you can’t get the sand tamped firmly enough, try putting a thin layer of fine (1/4” to 3/8” diameter) gravel on top of the coarse gravel instead. Fine gravel is more stable than sand but easier to level than the larger gravel underneath.

Julie

Further Information

6 COMMENTS

  1. I am having a versa lock wall installed along both sides of my driveway. One contractor quoted using a tamped gravel base and another quoted using a concrete or morter base. Is one better than the other? I live in PA so there will be a freeze/thaw effect.

  2. We have put up an above ground pool. and we have a need for a retaining wall..My husband wants to fill with pea gravel and told us that should hold the wall back. Is that safe? The pea gravel would be about 3 foot against the pool on just one side.

  3. @Kathleen, I would not recommend using pea gravel because it will shift around since it is smooth. You need gravel with sharp edges for friction so the gravel will not shift (in theory) when it is compacted. I would recommend going to your local rock quarry and get gravel that is no more than 1.5″ in size. I recommend gravel grade #57 because it is easier to rake, but you could use #5, #57 or #67

  4. I wish you folks (DIY advisers, nurseries, etc.) would sit down and agree on terminology. What is “coarse builder’s sand”? Is it Concrete Sand, or Mason Sand, or Silica Sand, or is it yet another type of sand I haven’t run across? I’m installing short retaining wall borders around my tree lines and my wife is putting in an above ground pool. Can we use the same sand for the base of both projects and Which One? I’d really like to get this started but every place I go has a different nomenclature for what they carry and just about every website calls it something else or just says “Sand”!

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