Would there be an issue with using composite shims to help level one layer of block on top of another?
Other possible relevant info

  • I am using 6in x 12in retaining wall block.
  • Max height is 3 blocks tall (plus capstone)
  • Using 3/4 in agg to backfill behind the block, inside the block cavity, and under the 1st layer of block.
  • Ground and 3/4 in agg stone are tamped and leveled prior to block placement
  • Capstones will be secured using landscape block adhesive.
  • I will probably squirt some landscape block adhesive into any gaps created around the shims.
  • I would expect to use shims on maybe 3 bricks where it's been tough to transition from one layer to another due to the hill slope.
  • Checking to make sure the shims do not cause any block wiggle once installed.


Shim Placement


1 Answer 1


These blocks are designed to be installed loose, and that tree's roots are going to win any disagreement they have with them. trying to make a permanent structure from these semi-permanent retaining blocks seems futile, especially in this location.

plastic, fibre-cement, or slate (etc) shims will not cause any significant weakening of the wall.

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