What is the best way to tie
a new block addition into an existing block
A. Dowel the new footing to the
original building with at least two #4 rebars. You’ll
need to dig to the bottom of the existing footing, drill it
horizontally, and grout in rebars that extend about a foot into
the new footing. The new footing should be at the same depth as
the existing footing and on undisturbed soil.
At the wall connection, vertically fasten a 3x3x1/4-inch
angle to the original wall with expansion anchors (see
illustration below). Provide a bond breaker on each leg of the
angle, and break out the end webs of the new blocks. Then, pack
the cores with mortar around the angle, and seal the joint
between the new blocks and the old wall with a good elastomeric
caulk. This will provide lateral support to the wall, but will
allow some minor vertical movement without cracking.