One of the first jobs I had when I started my career in the construction industry, back when I was working as an electrician, was installing electric resistance heating cables for a basement heating system. It took two people, one person pulled (me) while a second person pushed (my brother) and guided a small manual plow which installed electric heat cabling just under the surface of a sand layer. Concrete would then be poured over the sand; the result would be a heated floor. As it turned out, there was a high percentage of cable failures with this system, which resulted in many people having to install a new heating system.
What needs to be under a slab? Well, it kind of depends. Is the slab for a home or an accessory building? Is there heat in the slab? Is there a radon requirement? This quick post is all about what I like to see included under a slab and the reasoning behind the sequencing.