Undermount Drawer Runners: What Are They? Concealed Runners Explained

January 24, 2026

An undermount drawer runner is a specialised drawer slide fitted out of sight beneath the drawer base. This keeps the mechanism completely invisible when the drawer is open. It offers high stability, excellent running performance, and is widely used in professional cabinet making to preserve the natural timber look of the drawer sides.

What exactly is an undermount runner?

In contrast to side-mounted ball bearing runners or traditional drawer runner roller slides, this system sits entirely beneath the drawer box. The drawer rests on top of the slides and is usually locked in place via front locking clips. At the rear, a hook on the runner engages into a pre-drilled hole in the back panel of the drawer.

Acting like a concealed chassis on a rail vehicle, the runner carries the weight from below, leaving the side profile of the drawer completely free of hardware components. The load rests directly on the runner profile, enabling precise weight transfer into the cabinet carcass.

Types and variants

Undermount runners differ primarily in their extension length and integrated motion technology:

Extension length: A drawer runner full extension slide can be pulled out 100 % from the carcass, granting complete access to the drawer contents. A partial extension runner, by contrast, extends only around 75 % of the drawer depth.
Damping: Drawer runners with soft-close cushion the drawer as it closes. These are frequently paired with self-closing drawer runners that mechanically pull the drawer into its fully closed position over the final few centimetres.
Handleless opening: For handle-free fronts, push-to-open drawer runners are used. Light pressure applied to the front triggers a spring mechanism that ejects the drawer. Mechanically, this function is the exact opposite of soft-close damping.

Dimensions, standards, and typical values

Selecting the correct runner depends on the internal carcass depth and the dimensions of the drawer box. Typical nominal lengths for undermount runners range between 250 mm - 750 mm. Standard lengths in furniture construction include drawer runners 300 mm, drawer runners 400 mm, and drawer runners 500 mm.

To install an undermount runner, the wooden drawer box must be built to specific requirements:

Base recess: The drawer bottom must be recessed upwards from the bottom edge of the drawer sides (usually by 12 mm - 15 mm) to accommodate the runner mechanism.
Drawer side thickness: The material thickness of the drawer sides is limited because the runner occupies the space between the carcass interior wall and the lower edge of the drawer base. Common systems accommodate a maximum side thickness of 16 mm.
Load capacity: Standard runners are typically rated for 25 kg - 30 kg. For wider or deeper drawers, heavy-duty drawer runners with a load capacity of 40 kg or more are used.

Application and selection

The undermount runner is the standard choice in high-end joinery and interior fit-outs. It is favoured for solid wood drawers where exposed dovetail or finger joints along the drawer sides serve as a key design feature. When planning your installation, ensure the nominal length of the runner matches the internal cabinet depth and the exterior length of the drawer box. Cabinet fixings are typically spaced according to the standard System 32 grid.