Padding the Floor: When to Use Building Pads and When to Use Floors?!

As a result of Luke's post and a discussion I recently had with a colleague I find myself pondering...  What is the correct method of utilizing a building pad and a concrete floor slab?

There seem to be two typicality methods of using floor slabs and building pads:

• Using a floor and overlapping the building pad.  Typically shutting off the building pad when it can be seen.
• Using only a building pad (set to the same properties as your floor would be) as the floor slab.

What is your method?  Let's discuss.  Comment below.