Deep foundations are required when the shallow soils are not strong enough to support the loads from the structure. Pipe piles are commonly used in deep foundations and transfer the loads from building to stronger soil layers found deep underground. The loads are resisted through skin friction and point bearing. Pipe can be driven either open-ended or closed-ended, with points or plates. If driven with plates, the pipes can then be filled with concrete to add strength to the pile. Usually the money spent on plates, rebar, and concrete would be better spent on a larger, thicker pile. Pipe piles range in size from several inches to several feet in diameter and can be easily spliced to create piles hundreds of feet in length.