Fundamental doubt...Gross SBC vs Net SBC

[brick2020]

Hello All..
I have a fundamental confusion...

Should I size the footing for Gross SBC or Net SBC.

Because, if I size using Gross, some of the footings are under sized by 4-5% when compared with Net SBC? (but over all design is safe.. just the sizing is impacted.._)

Is there a logic for using one over other? or is there a standard practice for sizing?

 

[Ron]

I'm confused. Are you considering water table for the net SBC or a safety factor on the gross SBC to achieve net SBC? Please clarify.