Digging out crawl for a basement ??
I have a question if its possible to dig out a crawl space for a basement ? The house is a tri-level design with a rectangle foundation 30x50, 10 inch thick poured walls 48 inches tall (or deep) with corrugated plastic pipe drain tile and 1 sump well. 30x30 of the lower level is finished and 30x20 is a crawl with a "slush" concrete finish 2 inches thick. The crawl is dry with no signs of dampness ever. I was wondering if its possible to dig 4 feet deeper in the crawl and add concrete walls, I do not want to disturb the original foundation and do not need the whole 30x20 dug out, I was thinking more like a 15x15 area which would leave a minuimun of 5 feet to the foundation. I would like to move my laundry room down there and use the rest as storage, I would assume it would need 2 sump wells (1 runoff- 1 sewage/ejector). I am not planning on doing any of this myself and would call in professionals but dont know where to start.
I kick myself to this day for not getting the basement from the builder (built in 1999), it was $12,500 for the 30x20 to be dug as a basement but I could not swing it at the time as we were already upgrading to a bigger house than we had planned, our original choice was a smaller model with the basement. I was wondering if anyone had any guesstimates on what this would cost ? Thanks