A:Answer It does not matter really as the cabinet can extend up to 17 inches out. I guess you cannot use base cabinets, but would be hard pressed to find deeper wall cabinets. To install, it has a bracket for the back wall for positioning and rear support. It also requires bolt holes drilled through the bottom of the upper cabinet at about 10 1/2 inches from the rear wall. They are not spaced evenly (left to right) and were a little difficult to figure out where they go, but there is a bit of leeway if it isn't exact.