The Details
A sliding door is a type of door which opens horizontally by sliding, usually horizontal to a wall. Sliding doors can be mounted either on top of a track below or be suspended from a track above. Some types slide into a space in the parallel wall in the direction of travel, rather than the door sliding along the outside of the parallel wall.
The mechanism used to operate a sliding door is called sliding door gear. There are two standard types: top-hung or bottom rolling systems. Both types do not have a perfect seal. To reduce air- and smoke-tightness and improve sound insulation, brush seals are commonly used.
The ‘top-hung’ system is most often used. The door is hung by two trolley hangers at the top of the door running in a concealed track; all the weight is taken by the hangers, making the door easier to move.
At each end is a track stopper to absorb any impact made if the door is slammed and to hold the door in the open or closed position. All top-hung sliding door gear systems have a maximum weight limit per pair of trolley hangers.
As the door is hung at the top from two points, it also needs a bottom track/stay roller to prevent it from swinging sideways. A groove is cut into the bottom of the door which runs over this guide, preventing lateral movement of the door.