They just built a new house down the road from me and I was shocked when I saw what they did.
The basement was dug, and they built a wooden frame of 2x6's, covered it with green treated plywood, and that's the basement walls (below grade). I realize that treated plywood is meant to be waterproof, I question the life expectancy. What are we talking? Maybe 20 years at most, before the plywood starts to disintegrate, and the dirt starts falling in? And what about the frame, wont it warp inward? I did not even see a cement footing under it. I also question the savings. I know that cement block or a poured concrete foundation is costly, but treated plywood and 2x6's are not cheap either. So maybe they saved a couple hundred bucks today, but when the wood falls apart and nails rust thru, how much more will it cost to jack the house up to replace the foundation. Somehow I think this is a huge mistake.
One other thing, I can imagine how much water pours into that basement...