I have a basement with a dirt floor and an average 7.5 foot height to the floor joists above. I want to take out a foot of dirt and have a concrete floor poured so that I can finish the basement in the future. Of course the poles in the basement will need to be replaced because the footers for them are not deep enough to support lowering the floor a foot. My contractor says I can get the dirt out myself to save a ton of money in labor and all I need to do is give a two foot boundary around the base of the poles to keep them in place until he comes in and replaces the poles and pours the floor. -----Does this sound right?----- I have read that it is possible to dig around a footer (of the pole) as long as you leave a 45 degree angle of wider and wider dirt as you go lower. The footers of the poured walls are down farther than I need to dig so I am not too concerned about them. Since I can save about $10,000 in cost to dig out the 1300 square foot area and use the dirt in the yard it seems like a good plan. Is it a safe idea?

what is the difference? Which do I use and where?