A pole barn in North America is a barn that is essentially a roof extended over a series of poles. They are generally rectangular and do not require exterior walls. The roof is supported by the poles, which make up the perimeter of the barn. Walls may be added to pole barns but are not required for structural integrity. The roof can be gabled or hooped. Pole barns are often used for hay storage or livestock shelter, and larger structures are also used for indoor horse stables and riding arenas. This type of barn is not only very common in modern agriculture but is also used for other applications where large spaces are needed, including boat and truck storage, warehouses, strip malls, retail stores, public exhibit buildings at a fairgrounds, and related uses. Residential garages are also built as pole barns because of their quick construction time and efficient use of materials.