Where are you?

I should have mentioned, Northern Utah. So with the frost line it requires footing 42 or so inches below ground, so as the foundation gets toward the downhill side, on the front there are stem walls under the slab that are nearly 4 feet underground. So it's not like in temperate climates where they can pour footings at or near grade and put the slab on top.

Our foundations get expensive when building underground retaining walls on hillsides (you have) that consume lots of steel & concrete, requiring waterproofing, drainage & engineered backfill. Last walls I priced were running approx $1k per linear foot for that height just for the wall & a substantial footing required.

Check around locally. Budget what the GCs have quoted for a build $xxx per sq ft but price/bid each line item so you don't get surprised.

$37k for excavation is significant, $70k for foundation is moderate

Thanks gentlemen. Quick question though, wouldn't a full basement on a flat lot be considered a retaining wall on all four sides? This is essentially a full basement but with no downhill wall, two stepped-down side walls, and the back wall that's 10 feet high. Pretty much every house in northern utah is build this way.

The costs you save not building tall walls on the exposed sides will be spent on framing, exterior cladding, windows, exterior door(s) at that level plus landings, exterior lights, etc. Does this add a deck with railings to the level above the walk out? That is more costly than a flat slab on grade.

Your house overall should cost similar to other local homes under const plus or minus 10%.

Seems reasonable. We spent 40k on concrete alone for our basement and we have 9’ walls. We also have 4’ frost footings(that was 2 1/2 years ago). The excavation bid for you does seem excessive but may not be depending on your lot.

We are mid-build in Northern Utah and our excavation, rebar, anchors, footings and foundation were $110K. Full walk-out lower level with 10ft ceilings. Lower level is about 5k sq ft.

Thanks so much Ellen! My lower level footprint is about 1700 square feet so it seems my quote is on the high side. Actually very high. I take it yours was done in the past 12 months? If you are in the Park City/Heber/Coalville areas I'd love a referral to your excavator and foundation contractor if you can. peterhkemp at geeee mail .

We just sold our home in Heber and are building in Alpine. Our foundation was done in January so pretty recent. It sounds like your bid is very high.

We built our house in Heber 4 years ago so my costs there would be very out dated. I could still try and round up the contact info for the contractors though, if you wish.