Do they ever use concrete floor structures in homes? I don't mean a slab, I mean suspended floors, both 1st and second story. I visited a friend who made the loft of his barn out of concrete, poured in deeply corrugated metal pans. He built it to a ridiculous 160#/sq ft, but it's only 5-1/2" thick and spans 13'. I would think for residential use, it could be a lot thinner, and/or span greater distances. The best part is how little space it takes up, plus it is obviously fireproof. Now that I'm thinking of steel SIP's and metal framing, this would seem like a natural progression. Any ideas?

www.insul-deck.com

I think he has a different system than usual. Where I work, the upper floor looks almost liked corrugated roofing from underneath, and it is on steel bar joists. The barn I saw is 40' wide, and has 2 massive I-beams at 1/3 of the span, or a little over 13' on center. The metal pans have very deep corrugations, and rest on top of the I-beams. That's it, no other support. When you jump up and down on it, it almost feels like a slab, there is no deflection. As I said, it's engineered at 160# sq ft. I'll have to ask him more about it.

I am thinking 2" or 2-1/2", 22 ga, corrugated deck and a 5-1/2' total thickness (3 or 3-1/2" of cover) using shear studs.  If you google on wheeling corrugating or composite metal deck, you should find some load and span tables.  You can do a bit longer spans if you increase the gauge of the deck ....$$$$.  As you can imagine, single spans with no studs will have the shortest span as it will have little composite action.

Efficient beam spans at the perimeter of office buildings are usually ±30' (so 10' is a natural division), providing an even 5' window mullion spacing.

Metal deck on bar joists is hard to beat from an efficiency standpoint for small buildings.

Bruce

See ecospan-

http://www.ecospan-usa.com/

or

dietrich

http://www.dietrichindustries.com/canada/products/pdf/can/canada_96_99.pdf

both for residential applications

Hambro Flooring

Another concrete floor option I am looking at is SpeedFloor.  The process should make it quick and also relatively simple to include a PEX radiant floor where so desired.  It is strong enough to use for garage floors.