"could you give me an estimate of costs of slab (we would do a stem wall) vs. basement?"

This is so region specific that only a local person could supply any type of reasonable answer.

The first question is how common are basements in your area?

If they are common costs will not be as high.

Poured concrete with more than minimum rebar is probably a good start.

Thanks brickyee. In new construction they aren't common that common, most people do safe rooms or small shelters. However, they may become a lot more common now.

Basements are few and far between down here in the south, people only do them as a daylight/walkout basement. We did one, including a "safe" room, 6 sides of concrete with a fire rated door (inswing). Big enough for two cots and shelves with supplies, maybe 7x7.

As brickeye said, the actual costs are highly dependent on your locale, but here's a list of things that you will pay for moving from slab to basement:

1. Digging a big, deep hole.
2. Setting up Forms and Rebar for the pour.
3. Concrete, lots of concrete.
4. Waterproofing (don't skimp on this, it should be an asphalt and dimpled membrane combination.
5. More framing to get from basement to first floor system, very dependent on your design.

You still need a concrete slab, it just won't be as structural as it was before. And none of those things will be priced in hundreds of dollars, all will be thousands of dollars.

Brian

ok...have you looked into an all ICF home?

Miller Concrete out of Grove, OK does really good work. They travel all over the U.S. and would probably give you a really good rate for labor cost.
918-786-9570
Miller & Miller in Grove, OK is a private company categorized under Concrete Contractors. Our records show it was established in 1969 and incorporated in Oklahoma-- this is off of manta.com

OK I live in eastern PA and we did an office building on a slab with minimal excavating but lots of plumbing in it more than for a typical 3BR ranch around 2500 SF about $22K 10 years ago.( included disability entrance ramps)
Our current build foot print is 90X50 feet includes 3 car garage LOTZ of excavating we ran into rock and it is a walk out, has 9 foot ceiling.
18K excavating
22K foundation
This included an 8X36 foot Safe room under the porch will be a cold storage room this room has � 16" thick Roof (porch floor)
I grew up in SD. I was in a basement in Sioux Falls the night Manchester SD was wiped off the map. I have been through MANY tornados- even here in PA
PUT IN A BASEMENT!
Cut costs elsewhere but do the basement- this is a no brainer for you. You will get more SF for not alot of money compared to other ways to build.
Where I live resale would be nonexistent without a basement. I cant imagine regretting a basement.
Thank our Lord you were spared in the recent bout of storms
Good luck on your build