I want to fit a well-sealing garage door in my new house. The previous owner was a builder and built the garage with a stout concrete floor about 20cm deep but sadly the slab ends at the internal surface of the brickwork so the existing garage door hangs in mid-air rather than being based on the floor.
I want to extend the slab but would only need to add 7-10cm depth to take it to the front of the wall were I could use it for the bottom strip of a side-hung door. It can't really go further than this for a variety of reasons.
Seems simple enough, but that is a fairly thin strip of concrete (2.2mx20cmx7-10cm). Are there any special considerations when trying to join it with the old slab. I thought that perhaps using some rebars drilled into the old slab would do the job but should I be leaving in any sort of gap/join to allow for moment/expansion.
I've never done this before so would gladly take any expert advice! Mant thanks.