I have a house built in 1920 or so; 1000 sq feet. 2/3 of the house has a basement with concrete floors. The front third of the house has foundation walls that are only 5 feet; the walls sit on dirt that extends at a 45 degree angle to the dirt floor (which is level with the rest of the basement). Over the years, this front section has sagged a little and the foundation has cracked. I am also getting water leaking through the dirt. I would like to pour a concrete floor in this section over the dirt. Big question: how to hold up the 5 foot foundation walls? Should I dig underneath the walls and then pour concrete in sections? What other alternatives are there? I am looking to get this done soon. I have spoken to a concrete guy who wants dig away the 45 degree dirt and pour a footing 18in inside the 5 foot wall; then pour a 3 foot inner wall. I am unsure how this would help shore up the additional foundation. Any input??