My house is 60 years old. I have trenched the perimeter of the basement floor ( 25′ x 35′). The drain tile ditch is 23″ deep and 18″ to 24″ wide. All saw cut. I have also saw cut down the center for new main sewer line and 45 degree over (wye) for drains for HVAC equipment . Along walls and corners are other new drains, wash machine drain and bath room rough in. I have two large open areas, one is about 4′ x 12′ and another is 6′ x 8′. The existing concrete varies in thickness. A good average is about 2 1/2″ thick. A lot of it being 2″. The new concrete will be 3″ or 4′ thick. I want to use 3/8 rebar in the two large open areas and a heavy flat 6 x 6 wire in the trenches. My thought was to doll 3/8 rebar in the foundation wall for the entire perimeter, 3″ to 4″ into existing concrete wall with a 6″ stick-out. Dowels for the existing floor concrete are 1/4″ tapcons. All rebar areas on 24″ centers, 18″ centers for wire mesh. For interior ditches: I can use a 2 1/4″ Tapcon not fully screwed into existing floor concrete, 1 1/4″ into existing floor concrete with a one inch stick-out. Tie wire mesh to one inch stick-out on one side of ditch and wire tie to opposite side also with a one inch Tapcon stick -out. In the large open areas: using all 3/8″ rebarb, my thought was to use one 1 1/2″ Tapcon through a piece of 1/4 x 1/4 x 1 1/2″ aluminum angle 1 1/2″ long ( I have plenty) screwed to existing concrete floor. Set the 3/8 rebar on the 1 1/2″ long aluminum angle and wire tie it off. The other end of the rebar tied to the 6″ 3/8 rebar stick-out from foundation wall. Open areas with 3/8 rebar I will install 3/8 rebar in opposite direction and tie for 24′ squares. For perimeter ditches: Tie 6 x 6 wire mesh to the 2 1/4″ Tapcons with a one stick out from existing floor concrete. Tie opposite side of 6 x 6 wire mesh to 3/8 rebar with 6″ stick-out from foundation wall.
Whatta ya think? I want to minimize cracks by using the mesh and rebar. Another concern is that the Tapcons and/or aluminum angle will only have only an inch of new concrete cover because of the 2′ to 2 1/2′ 60 year old concrete floor.