Pad vs Foundation Slab - please help

[revituser195]

I have a pad creating the excavation in my topo. So with the pad there how does a foundation slab get used & how are the two supposed to interact?

Since the pad goes the width of the excavation, it doesn't correctly represent the slab as the slab shouldn't penetrate the foundation walls.

All I really want is the foundation slab. Do I need both? What's the difference? Anyone care to fill me in?

Thanks,
Rob

[wmullett]

I think a lot of this is up to you and what you need to get out of your model. Do you cut your pads to full excavation width and use graded regions to backfill? We only use the pads to the outside of foundation walls and most times, we put the granular material with the grade floor slab.