A sliding glass door or patio door, a type of sliding door in architecture and construction, is a large glass window opening in a structure that provide door access from a room to the outdoors, fresh air, and copious natural light. A sliding glass door is usually considered a single unit consisting of two panel sections, one being fixed and one a being mobile to slide open. Another design, a wall sized glass pocket door has one or more panels movable and sliding into wall pockets, completely disappearing for a ‘wide open’ indoor-outdoor room experience.
The sliding glass door was introduced as a significant element of pre-war International style architecture in Europe and North America. Their precedent is the sliding Shōji and Fusuma panel door in traditional Japanese architecture. The post-war building boom in modernist and Mid-century modern styles, and on to suburban ranch-style tract houses, multi-unit housing, and hotel–motel chains has made them a standard element in residential and hospitality building construction in many regions and countries.
Sliding glass doors are popular in southern Europe and throughout the United States, being used in: hotel rooms, condominiums, apartments, and residences; for access to upper balconies; for large views out – enhanced natural light in; and to increase incoming fresh air. In addition Sliding glass doors are commonly used in some regions as doors between the interior rooms of a home and a courtyard, deck, balcony, patio, and a garden, backyard, barbecue or swimming pool area. They are often called Patio doors in this context. They are also used in interior design, often in offices and automobile sales areas, to give soundproof but visually accessible private office space. In residential interiors they are used, often with translucent ‘frosted’ glass replicating a traditional Shōji door, to allow daylight to penetrate further into the dwelling and expand the sense of interior spatial size.
Sliding glass door frames are often made from wood, aluminum, stainless steel, or steel, which also have the most strength. The most common material is PVC-plastic. Replacement parts are most commonly needed for the moving-sliding parts of the door, such as the steel rollers that glide within the track and the locking mechanisms.