- Q.It’s not unusual
for a foundation to be slightly out of square. If the
house has brick veneer siding, it’s sometimes
necessary for the first course of bricks to overhang
the concrete foundation. What is the maximum safe
overhang in such a situation?
engineer Clayford Grimm responds: To provide
structural stability, at least two-thirds of a
brick masonry wythe should bear on the foundation.
Three-inch brick veneer should not overhang the
foundation by more than 1 inch, and 3 5/8-inch
brick veneer by not more than 1 1/4 inches.
One reason this condition occurs fairly often is
that the American Concrete Institute’s
Standard Tolerances for Concrete Construction
and Materials (ACI 117) provides that footings
may be misplaced as much as plus or minus 2 inches.
One solution to a misplaced footing is to relocate
the wall. The Specifications for Masonry
Structures written by the Masonry Standards
Joint Committee (MSJC99) provides that the location
of walls may differ from the intended location by
as much as plus or minus 3/4 inch. So as long as
the wall location can be adjusted in the right
direction, it is possible for 3 5/8-inch brick
veneer to stay within the allowable tolerances for
both masonry and concrete.