How can I fit an oversize retaining wall base adjacent to sidewalk?

Question

I'm going to build a small retaining wall (about 3' tall) along the sidewalk in front of my house using Versa-lok standard blocks. They recommend compacted gravel base about 18" deep for blocks that are 12" deep. This would result in the gravel base a few inches in front and in back of the first course of blocks. Because of my sidewalk, I cannot excavate in front of the wall to have the gravel base in front of the wall. How big of a problem would this pose for such a short wall? I'm also planning to use geogrid reinforcement fabric, proper drainage, etc.

Thanks in advance.

Answer 1

I think you're asking about width, and not depth. I'd simply excavate an inch or three under the sidewalk and fill it with your substrate, then set the wall tight to the sidewalk.

If this is not possible, build the base as wide as is practically feasible and compact it well. It's unlikely that you'll have problems with a three-course wall.