Mast Climbing Work Platforms

A mast climbing work platform, often called a mast climber or MCWP, is a powered platform that travels up and down one or two vertical masts attached to a building or structure. The platform carries workers, tools and materials along a facade, and it can be stopped at any height to create a working deck. Mast climbers are used for facade installation, bricklaying, cladding, glazing, insulation, painting, renovation and maintenance, on everything from low-rise housing to tall buildings, chimneys, silos and ships.

The mast climber sits between scaffolding and powered access equipment. Like scaffolding, it provides a long, stable working deck in front of a wall and can remain on site for weeks or months. Like an aerial platform, it moves the workers and their materials to the right height at the push of a button, so the work level can follow the progress of the job. On many projects it replaces a large area of fixed scaffolding and reduces the need for cranes to lift materials to the facade.

Brief History of Mast Climbing Work Platforms

Mast climbers grew out of the rack and pinion technology developed for construction hoists. Alimak, founded in Sweden in 1948 by Alvar Lindmark, was a pioneer of rack and pinion lifting, and the company’s early work on hoists and platforms in the 1950s and 1960s laid the basis for the modern industry. The principle was simple and robust: a motor on the platform drives a pinion that engages a toothed rack on the mast, so the platform climbs the mast directly.

In the following decades, mast climbing work platforms became established in Europe as an alternative to scaffolding for masonry and facade work, and manufacturers in the Netherlands, Italy, Germany, Canada and other countries developed their own ranges. In North America they became common for masonry and precast facades. Over time, platforms became longer and stronger, twin mast configurations allowed decks of 20 m or more, and safety standards, including the European standard EN 1495, set requirements for design, overload protection and emergency systems. Today mast climbers are part of the equipment portfolio of access specialists and rental companies in many countries.

How a Mast Climbing Work Platform Works

Base. The mast stands on a base frame, often with outriggers or a wheeled chassis. Some bases are towable trailers for quick setup.
Mast. The mast is made of modular steel sections, typically about 1.5 m long, bolted one on top of the other. A rack runs along the mast for the drive pinions.
Drive unit. Electric motors with gearboxes and brakes drive the pinions. Most platforms use mains power on site, and some smaller units use petrol or diesel.
Platform. A deck with guardrails is attached to the drive unit and extends on one or both sides of the mast. Extension decks can bring the working edge closer to an irregular facade.
Ties. The mast is tied to the building at regular intervals, as specified by the manufacturer, to keep it stable. Freestanding heights without ties are limited.
Safety devices. Overspeed safety brakes, overload detection, limit switches at the top and bottom, emergency lowering and guardrails with toe boards are standard features.
Erection. Mast sections and ties are added from the platform itself as the job progresses, often using a small crane or hoist mounted on the deck.

Types of Mast Climbing Work Platforms

Single Mast Platforms

One mast with a platform on one or both sides, for narrow facades, lift shafts, chimneys and smaller buildings. Platform lengths are typically up to about 10 m on each side.

Twin Mast Platforms

Two masts with a long platform between and beyond them, used for wide facades. A twin mast platform can often carry several tonnes and provide a deck of 20 to 30 m or more.

Trailer-Mounted Platforms

Light mast climbers mounted on towable trailers, set up quickly for short jobs such as window replacement or maintenance.

Heavy-Duty Platforms

Robust units for heavy materials such as stone, precast panels or large glazing units, often with integrated cranes.

Transport Platforms

Mast-guided platforms designed mainly to carry materials, and in some jurisdictions people, between levels, forming a hybrid between a work platform and a construction hoist.

Size and Capacity

Configuration	Typical platform length	Typical load capacity
Single mast	about 3 to 10 m each side	about 1 to 3 t
Twin mast	about 10 to 30 m and more	about 2 to 5 t or more
Trailer-mounted	about 5 to 12 m	about 0.5 to 1.5 t

Figures are indicative. Maximum heights with ties commonly exceed 100 m.

Attachments and Accessories

Common accessories include extension decks, bridging sections between platforms, cantilevered corner platforms, protective roofs, weather enclosures, material cranes and hoists, glazing manipulators and lighting. Mast climbers can also be fitted with brackets that allow the platform to work around balconies and projections.

Main Manufacturers

Alimak, the Swedish rack and pinion specialist, which also owns Scanclimber and the Dutch company Hek.
Fraco, a Canadian manufacturer of mast climbers and transport platforms.
Geda, a German manufacturer of hoists and mast climbing platforms.
Safi and Maber, Italian manufacturers.

Main Uses of Mast Climbing Work Platforms

Bricklaying and blockwork on new buildings.
Installation of cladding, curtain wall and precast panels.
Window and glazing installation.
External insulation and render systems.
Painting, cleaning and facade renovation.
Work on chimneys, silos, towers, lift shafts and ships.

Planning a Mast Climber Installation

Facade and structure. Tie positions and anchor loads must be agreed with the structural engineer so the building can take the forces.
Ground conditions. The base loads are concentrated, so foundations, slabs or basement roofs must be checked.
Layout. Platforms are arranged along the facade with the right distance from the wall, and corners and projections are planned in advance.
Loading. Materials must be distributed along the platform within its rated capacity, which depends on the configuration.
Power supply. A reliable electrical supply at the base is needed for the drive units.
Erection and dismantling. Only trained installers should erect and alter mast climbers, following the manufacturer’s instructions and inspection routines.
Coordination with other trades. Tie positions, platform positions and the sequence of facade work should be agreed with the trades that will use the platform, so ties do not obstruct panels or windows still to be installed.

Mast Climber or Scaffolding?

Access to the work face. A mast climber keeps the deck at the ideal working height, so masons and installers do not have to work above shoulder height or bend down to the deck.
Materials handling. The platform carries pallets of materials directly to the work level, reducing crane time and manual lifting.
Setup time. On large facades, a mast climber can often be installed faster than a full scaffold, although scaffolding remains more flexible on complex shapes.
Multiple levels. Scaffolding lets several trades work on different levels at the same time. A single mast climber serves one level at a time.
Weather protection. Scaffolding is easier to sheet completely, while mast climbers need dedicated enclosures.

Safety

The main risks are falls from the platform, overloading, loss of stability if ties are missing or incorrectly installed, and people struck by falling objects or by the moving platform. Guardrails and gates must be in place, the rated capacity must never be exceeded, and ties must be installed as the mast grows. Exclusion zones below the platform, protective fans or netting and good housekeeping reduce the risk from falling objects. Wind speed limits must be observed, and the platform must be inspected before use and after changes or bad weather. Industry bodies publish guidance on safe use of mast climbers, and operators need specific training in their controls and emergency procedures.

Trends and Technology

Manufacturers are improving modularity, speed of erection and load capacity. Control systems with load monitoring, levelling of twin mast platforms and remote diagnostics are becoming common. Battery-powered units reduce reliance on site power. Mast climbers are also used alongside robotic tools for facade installation and with integrated weather protection, extending the working season.

Key Terms

Rack and pinion: a drive system in which a gear climbs a toothed rack on the mast.
Tie: a connection that anchors the mast to the building.
Twin mast: a configuration with two masts carrying one long platform.
Freestanding height: the maximum height of mast without ties.
Overspeed brake: a safety device that stops the platform if it descends too fast.
EN 1495: the European standard for mast climbing work platforms.

Frequently Asked Questions

What is the difference between a mast climber and scaffolding? Scaffolding is a fixed structure with many working levels. A mast climber provides one movable working deck that goes up and down, so workers and materials are always at the right height.

How high can a mast climbing work platform go? With proper ties to the structure, mast climbers can work at heights well above 100 m.

Can a mast climber carry materials? Yes. Carrying materials such as bricks, blocks and panels is one of its main functions, within the rated load and distribution limits.

Do mast climbers need a crane to install? Usually not. Mast sections are often added using a small crane or hoist on the platform itself.