A sliding roof is a roof system designed to roll back the roof on tracks so that the interior of the facility is open to the outdoors or to let the sunlight in Sliding roofs are sometimes referred to as operable roofs or retractable skylights. Sliding roofs are used in residences, restaurants and bars, swim centres, and other facilities wishing to provide an open-air experience at the push of a button. While any shape is possible, common shapes are flat, ridge, hip-ridge, barrel and dome. A residence might incorporate one or more 3′ by 5′ retractable; a bar or restaurant a retractable roof measuring 20′ by 30′; and a meeting hall a 50′ by 100′ bi-parting-over-stationary.