I would like to replace an existing retaining wall (pictured) which is falling apart with one that is as close as possible to the fence line to reclaim some of our back yard from the drive way. Our plan would be to then cut the asphalt back from 14' to the side fence to ~10' and increase the grass area. It is presently about 3' tall.

The look we are going for is Quikwall on cinder blocks, painted white.

We live in Canada and the frost line where we live is 48". My first question is if I want to build a wall of the similar height out of cinder blocks/mortar/rebar, do I really need to dig down 4 feet and pour a 16" wide concrete footing?

My other question is, when digging up the existing wall, should I brace the fence with 45 degree 2x4s?

I'm open to suggestions and have the manpower, time, and some friends who are landscapers to help out, but if I have to lay more than 2 courses beneath the ground I can see the costs escalating very quickly and would like to avoid that if possible.



  • How well do the dry fitted concrete block walls (Keystone or Versa-Lok) do in your location? Where I am these require only a shallow crushed rock base. May 16, 2020 at 17:26
  • They do fine and would work in this scenario. I'd say that is probably what 90% of people do, and build it on crushed rock however my wife and I are going for a specific concrete aesthetic with all of our hardscaping May 17, 2020 at 3:55

1 Answer 1


I would not be going 4’ deep. For a small wall like that I would want a wider footing 16” sounds good but would go 18”deep max , I don’t see any way for there to be hydraulic issues that may require a deeper footing. I would have rebar in every other hole and back fill them all with concrete. On the back side I would lay a drain in a sock at the footing or base of the wall and fill around it with rock and cover the rock with landscape fabric. Then the only thing you have is the dirt and 18” should hold up fine possibly 12” depending on how hard it freezes in your area.

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