Get free estimates from concrete companies near you. Your final cost will depend on the slabs size, thickness, and if you any special reinforcement such as wire mesh or rebar. Four to eight inch thick concrete slabs are mainly used for driveways, patios, sidewalks, and garage floors. Adding radiant heat, extra dirt work, or grading convrete the sub-base costs extra. If you want to add additional reinforcement due to poor soil conditions, or if you’re worried about big cracks, put some structural reinforcing metal in the concrete foundation with either wire mesh or rebar. Also, hoow your going to go with 4″ thick slab, reinforcing metal is highly recommended to make your slab structurally sound.