Pile foundations are deep foundations. They are formed by long, slender, columnar elements typically made from steel or reinforced concrete, or sometimes timber. A foundation is described as 'piled' when its depth is more than three times its breadth (ref. Atkinson, 2007).

A pile foundation is a type of deep foundation, actually a slender column or long cylinder made of materials such as concrete or steel which might be cast-in-situ or driven at the place used to support the structure and move the load to the desired depth by end-bearing or skin friction.