Well Mr. R. You seem to be very intelligent when it comes to engineering. I never use 4 in slabs myself the thread started out with the use of 4 inch slab. It is used very commonly with residential construction. I commonly use 5 to
6 inch slab on grade and at least 6 inch for composite sections. And, it is the geotech engineer to inform us on the correct soil preperation prior to pouring a slab on grade. If you remember I suggestion control joints in the 4 inch slab at the beginning. With this in mind why do you consider yourself the moderator of the alt.architecture news group for the fun of it?Chuck... ____________________________________________________________ Charles I. Dinsmore, PE SE RA, M.ASCE ~ snipped-for-privacy@gmail.com