folds the door back with a single horizontal track on each side (which is mounted at the top of the wood frame) and a roller, (mounted to the top of the door on each side. A hinge on each side that attaches to the bottom of each side of the garage door. Using track hardware, a car can be parked much closer to the door, as the whole door, when in the open position, rests completely inside of the garage door header. Track type hardware has much less arc when raising and lowering the garage door as opposed to jamb type hardware. Sectional garage doors Sectional doors are usually constructed of three to eight panels and slide up and overhead. Sectional doors occupy exactly the same amount of internal garage space as a monolithic door. Sectional doors have two advantages over single panel monolithic doors: Sectional doors do not require any space outside the garage to open. A vehicle may park very close to the garage before opening the door. Each panel of a sectional door has its own connection to the door track. This increases reliability and robustness compared to monolithic doors, which have only a few track connections for the whole panel. Garage doors can be made out of many materials, but steel, aluminum, wood, copper, glass, and vinyl (polyethylene) are the most popular materials. Some manufacturers incorporate foamed-in-place polyurethane insulation within the monolithic panel and sectional garage doors. The side sliding sectional door A lot of space under the garage ceiling. Can use the entire ceiling of the garage. Fast access to the garage Roller doors Roller doors (sometimes called "sheet doors") are usually constructed of corrugated steel. They evolved from cover window and door coverings. Other materials can be used (e.g.; transparent corrugated fibreglass) where strong impact resistance is not required. Corrugations give the door strength against impacts. A typical single-car garage roller door has a preloaded spring inside the rolling mechanism. The spring reduces the effort required to open the door. Larger roller doors in commercial premises are not sprung (except in the US) and use a manual pulley and chain system or a geared motor to raise and lower (roll up and roll down) the door. Roller doors cannot be effectively insulated. In the UK (and other parts of the EU), 'insulated' roller garage doors are available, using an aluminium lathe filled with polyurethane