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Attaching CMU wall to concrete slab-retrofit

richfield95's picture

Our 40 year old garage has a concrete slab then an approximately 3ft high CMU wall on top.  Most of the bottom row of block is below grade and whatever motor originally fixed the block to the slab is gone and there does not seem to be any type of rebar.  We live in upstate NY And when the ground freezes, the walls move slightly, enough that the man door doesn’t latch.

We tried digging around the outside of the garage and installing drainage with crushed stone thinking if the ground didn’t exert pressure on the block, that the movement would be less.  That had only a minor improvement.  Are there other options we could try besides drilling rebar through the block in to the slab?

Unclear:  Is the block (post #215882, reply #1 of 3)

Unclear:  Is the block sitting on top of the slab, or does the block rest on a footing below grade, with the slab poured against the block?

I'm guessing the latter, and the main problem is likely to be that the floor of the garage is freezing and expanding as it does.

I can't see how running rebar into the slab would help at all.


Of all the preposterous assumptions of humanity over humanity, nothing exceeds most of the criticisms made on the habits of the poor by the well-housed, well-warmed, and well-fed.  --Herman Melville

Block is sitting on slab (post #215882, reply #2 of 3)

One slab was poured for the garage floor, then the block was laid directly on top of the slab. The problem is with the slab moving, just not sure if we can or would want to fix the block walls to the slab

Drill holes in the slab, (post #215882, reply #3 of 3)

Drill holes in the slab, epoxy rebar in every 2' or so then fill then knee wall with concrete.

Florida Licensed Building Contractor, 50 years experience in commercial remodeling, new homes, home remodeling and repairs and all types building maintenance.