I need to cut a trench in a 4" thick concrete slab for plumbing work, the
trench needs to be 20" wide, and the trench runs along the direction of an
exterior wall. However, the centerline of the trench is only 18" from the
wall, so when the trench is cut, there will only be 8" of slab left on the
side of the wall.
Is 8" enough of the slab to be left there? or should I just knock out the
8" and make the trench 28" wide?
When I am done with the work, and need to pour concrete to fill in the
trench, I will need to drill rebars into the old concrete slab, will having
8" of slab on that one side help any?
If I knock that 8" out, will I drill the rebars into the 8" thick concrete
block wall instead?