I am looking to help a friend repair cracked sunken garage floor. The apron 8" out past where the garage door closes and 8-10" into the garage have cracked and sunk near the inside block walls. I have poured sidewalks, driveways and pads, but never a garage floor. At first, I thought he just wanted the outside replaced, no problem, but inside. I am not sure how to cut the floor at the block wall.

LB

I have to ask you to first find out or figure out why the inside floor sunk so the repair doesn't do the same.

How much of a drop is it and give details on slopes and size

How old is the existing garage floor and what's the downspout situation there?

What's the out side topography like?

Does this garage have a block foundation?

If it does then there could be a major problem here. The ( Apron ) sits on a block wall for bearing if the foundation was done correctly, which is still part of the floor. In front of the building wall is the apron which should not be part of a fixed floor without expansion ans rebar tie ins. The apron past the garage floor floats and moves.

I'm a Crete and mason Have seen aprons sink or crack or break up but never saw one sink at the door which in on the inside of the wall and in front of where the door closes there should be a block wall under that door opening.