We are going to convert our back porch into a sewing/hobby room for the wife. The porch is 10'x12' on a slab which is 4" lower than the main house slab. My question is about the necessity and technique of bonding the overlay to the old slab. I know in most construction the process is to drill and epoxy rebar into the adjoining slab but that kind seems like overkill for a small slab project like this. I thought maybe just drill some rebar pins down into the old slab floor then pour the overlay on top.
Any thoughts about bonding these slabs together?