The primary components of mast climbers are a vertical tower typically composed of modular stacked units resting on either a mobile chassis or stationary beams, a work platform that travels up and down the tower, and a drive unit that moves the platform up and down. Mast climbers use either a gas-powered hydraulic power system or an electric motor power system. Mast climbers can be further classified by the drive system, using either a ratcheting or rack-and-pinion drive.

Mast climbers may be designed and used with a single tower or twin towers. Some modules are designed to operate as free-standing units up to a manufacturer-specified height. Most mast climbers are structurally supported by an anchorage system made up of ties and anchor bolts attached to the building being worked on. Design of the anchorage system (which includes a specified spacing schedule) and use of the correct bolts and ties are thus extremely important to ensure the safety and integrity of a mast climber.

Typical Uses
Mast climbers are typically associated with high-rise construction, but they are used most often on structures up to 60 feet in height (Inglesby 2008). The heights at which mast climbers are used vary according to their specific application and type of system. Hydraulically-powered ratcheting drive systems are commonly used at lower heights, for masonry work. Rack-and-pinion systems, on the other hand, are typically used at elevations of 30 feet and higher and can go as high as 1,000 feet. These systems are commonly used for glazing and drywall applications. In addition to these applications, mast climbers are also used in architectural cladding and mechanical work (for instance, to mobilize and install heavy-duty steel pipe and duct work).