We wanted to be sure the foundation walls were properly supported during the underpinning process, so we worked in short sections, starting in the corners.
We added the upper form boards and poured the upper part of the footing, using the nonshrink grout instead of standard concrete.
After forming and pouring the corners, we continued the process in alternating 6-foot sections around the perimeter, placing the rebar so that it extended past the ends of the forms.
As we filled in adjacent sections, we tied the rebar together to create a continuous monolithic footing. Since we had to chip away part of the old footing to gain access for pouring the concrete, we formed the new footing to maintain the original 20-inch footing width.