PVCu sliding patio doors can be specified as either in-line sliders or as tilt and slide doors.
In-line sliding patio doors are generally made up of one fixed glazed panel and one which slides across it to form the opening.
Early patio doors, especially in aluminium frames, had the sliding section on the outside of the fixed panel and posed a security risk. The sliding section could often be easily lifted out completely to gain access from outside.
Modern PVCu sliding patio doors have the sliding section on the inside of the fixed panel – this not only reduces the security risk but also means that the sliding track is better protected against inclement weather.
For wide brick apertures, PVCu sliding patio doors may have to be split into more than two sections. Three part PVCu sliding patio doors would generally have the centre pane sliding across one or both of the adjoining fixed panels.
Four part PVCu sliding patio doors would normally have the centre two sections sliding, one to cover the left fixed panel and one to cover the right fixed panel.
Tilt and slide patio doors offer an additional function to in-line sliders as the sliding door can also tilt inwards into the room. This two way opening facility increases both the complexity of the opening mechanism and also the price.
The major benefit of tilt and slide patio doors over in-line PVCu sliding patio doors is the ability to provide ventilation without the door being open for access.