The Benefits and Drawbacks of Stone Keep Castles Stone keep castles had several benefits over the motte-and-bailey castles they replaced. They were unquestionably stronger defensive fortifications—until the late 12th and early 13th centuries, stone keep castles were virtually impenetrable. They could also be much larger: while the typical motte-and-bailey castle might have been 20 to 30 feet high and 100 feet wide at its base, a stone keep could reach 40 to 60 feet high and cover an area more than 300 feet on a side. However, these advantages came with drawbacks: stone quarrying and transportation are extremely time-consuming processes; therefore, a lord wanting to build a stone keep would have to wait until enough rock had been extracted from the right location to make construction feasible. Also, since stone is heavy, a lord wishing to construct a large structure would need a lot of helpers to transport it where it was needed. Finally, because stone is difficult to work with, building a stone keep required skilled artisans who were not easy to find. Only lords who could afford to hire workers away from their other projects could build such structures. In conclusion, a stone keep is strong and beautiful, but it takes a long time to build and there aren't that many people who can do it. The lord who could afford to hire builders away from their other projects would have seen his castle built before anyone else's.