Expert: Dan Griffin - 4/25/2008

Question
I live in the Midwest with a max frost line of 42". I had a block contractor put a foundation wall up (42" deep footing with CMU knee wall) for an addition to my existing detached garage (that has an existing 42" deep footing with CMU knee wall). I noted on the drawings that the block was to be reinforced as per code, which he did at the appropriate spacing.

I also noted for him to grout every core solid to grade, which he did NOT do. Is this a problem? I am under the impression that water will get into those cores below grade and will freeze, thus breaking up those un-grouted cores.

Is this correct? Should I make sure these cores are grouted?

Answer
The grouted cores are for strength, not water.  The outside of the below grade block work should be damp proofed.  The usual treatment would be a tar based sealant protected by a sheet good type material.  If you have known water intrusion problems, there should be a French drain/gravel system in place lower than finish floor.