When lifting tilt-up panels, should you operate the crane on or off the floor slab? A general contractor tackling his first tilt-up job discusses how difficult it is to evaluate the pros and cons of each option. One of his main concerns on his project was minimizing floor cracking that might occur as a result of the crane entering and exiting the floor slab and operating on the slab. For most tilt-up jobs, the foundation elevation is anywhere from 4 to 18 inches below the finished-floor elevation, leaving the slab edge virtually unsupported. After weighing many factors, he opted to use a truck-mounted crane and operate it off the floor slab to lift stack-cast panels on the floor perimeter.