Reviewing the Basics

To identify the components of the sliding door hardware systems, one can start with the historical fundamentals and expand from there, adding the new elements introduced in more recent engineering and manufacturing advances. For architects, the following are most important in the design and specification of a project leveraging top-hung sliding hardware:

Track

Sliding door tracks come in different shapes (sections) that offer varied benefits and lend themselves to certain applications. Box type track, mentioned earlier, holds the door securely and is less prone to contamination than others. By eliminating the potential for trolleys to “jump the track” and because they are easier to keep clean than other types, box sections are generally a solid, economical specification for any need.

Compare this to the I-beam track, on which dual trolleys are set on both sides of the I-section, and the C-shaped track, which may have a raised lip on which the shaped trolley rests. The light I-beam, typically of extruded aluminum, recalls their zinc-plated steel cousins used for heavy-duty agricultural uses, with the exposed trolleys imparting an industrial feel. The C-shaped track extrusions are readily adapted to shapes and curves, letting designers create sliding doors that bend, arc, and even turn corners.

Tracks are mounted above in a manner depending on the selected section, door need, and architectural assembly. Track mounting options for top-hung hardware systems include side mount assemblies fixed to a wall, soffit edge, or other vertical surface structure as compared to ceiling surface mount, where the hardware assembly extends down from the horizontal plane. Ceiling recessed mount is a third attachment option, in which the track is buried up and within the ceiling plane, lending a clean and visually unobtrusive condition.

Trolleys

Also known as the carrier, the trolley is a wheeled carriage device that travels along the overhead track. Considerations for the trolley hardware should reflect the mounting approach, the weight of the door, and whether the track has curves or corners. All of these will affect the bearing weight on the rolling hardware, to be calculated by the engineer or architect. For this reason, trolley designs vary quite a bit.

Suspension System

The suspension system links the trolley to the top of the wall or door panel in a top-hung configuration. The suspension hardware is often surface mounted and therefore visible; however the suspension can also be neatly concealed within the door itself. The latter option, often called buried suspension as well as concealed or hidden suspension, is attractive and suitable for carefully detailed, high-end interiors.

Door Guides

These are used to keep door or wall panels moving in line with their overhead tracks and to prevent them from swinging. Guides may be attached to the floor or wall (or both), eliminating the need for any modifications to the floor and thus providing a barrier-free threshold. Compare this to a continuous floor guide, which is required for very heavy sliding panels, wide panels, or panels that are designed to slide farther than their own width.

Unlike the raised continuous floor track typical of inexpensive residential-type sliding screens and patio doors, for today's top-hung sliding hardware systems the continuous floor guide can be a clean, narrow slot opening recessed into the floor materials. Again, it requires no raised threshold, and the door slides in a solid manner with no sway. Architects and contractors should plan to use a continuous floor guide whenever:

• Door or wall panels are heavy and require control.

• Any panel slides more than its own width.

• A panel's height-to-width ratio is too large to avoid sway at the unguided end.

• Any panel widths exceed 5 feet.

Door Stops

Another key piece of hardware built for top-hung and other sliding systems is the door stop, which can be exposed or concealed and serves to ensure the door or wall panel never slides beyond its intended reach. The track stop is inserted inside the track, hidden from view but providing for function and safety all the while. Alternatively a bottom door stop is a visible, floor- or wall-mounted component that limits the endpoint of a slide run. A standard “door stop” called out in specs is assumed to be the wall-mounted version, analogous to a stop used for a pivot or swing door. Materials of the stops should match the hardware, with metals such as stainless steel and hard rubber head elements or collars.

In addition to these five hardware components—track, trolley, suspension, guides, and stops—there are many other elements and options that may be considered depending on functionality and aesthetic expression. Panel materials, for example, may include wood, glass, metal, and a combination of these as well as a number of any of the above composite panels and manufactured materials, such as structural colored and shaped acrylic panels. But the basics of top-hung sliding design requires the designer to be familiar with and work with the core five hardware components to design and deploy a successful sliding system.