Root Cellars in PZ Suggestions Posted July 5, 2016 The effort deposed on digging is going to be costly, that`s clear. We can`t just give it away as an easy alternative. Also you will need a ladder or some stairs, and something to cover it up, because I don`t think you would like to eat your bolognese side by side with some zombies. It might take a couple days to do that, because besides digging the room you need to ventilate it, maybe make the walls stronger ( most probably concrete ), so you will need a lot of materials and time. Good ideea as an end game improvement.