I am about to start excavating for a crawl space, and continuing on to build the crawlspace from there. 23 x 48, and 16 x 27. Westchester County NY, northern western lower cost part of County. The house foot print is a T, everything square edges. The house is modular. The 'base' part of the T is 16 x 27 and is in an area of ledge rock. I m going to have to get 4' or so of ledge rock off to get to grade, and then keep going to go below grade. I m assuming that I can pin the crawl space wall to the ledge rock. I am assuming that I will not have to go below the frost line for this part of the crawl space, as the rock will be considered part of the foundation. For the 23 x 48 part there is not any ledge rock appearing, and I m assuming the crawl space wall will be 18" (?).
Questions:- back hoe or excavator for where there is no ledge rock? what size of bucket? what size of backhoe or excavator - 16K, 24K? for the ledge rock I will hammer it with a hammer on the 24K - good plan? Any insights / answers appreciated.