Construction Hoists

A construction hoist, also called a builder’s hoist, site lift or rack and pinion elevator, is a temporary lift that carries workers and materials up and down the outside of a building or structure during construction. It consists of a car or platform that travels along a vertical mast tied to the building, usually driven by electric motors through a rack and pinion system. As the building rises, sections are added to the mast so the hoist can reach each new floor.

On high-rise projects the construction hoist is as important to the site logistics as the tower crane. The crane lifts heavy and bulky loads, while the hoist moves the workforce, tools and the large volume of smaller materials needed for fit-out. A well-planned hoist system reduces the time workers spend climbing stairs and waiting, and frees the crane for work only it can do. Hoists are also used on industrial structures such as chimneys, silos, bridges, power plants and ships.

Brief History of Construction Hoists

Early building sites used ropes, pulleys and winches to raise materials, and rope-driven material hoists with a simple platform in a tower were common for much of the twentieth century. These machines generally carried materials only, and workers used ladders and stairs.

The rack and pinion hoist changed this. Alimak, founded in Sweden in 1948, is closely associated with the early development and spread of the rack and pinion principle for construction and industrial lifts. Because the drive unit climbs a toothed rack on the mast, the hoist can be extended simply by adding mast sections, and safety devices can act directly on the rack. From the second half of the century, rack and pinion hoists became the standard for carrying people on tall building sites around the world. Later developments included frequency-controlled drives for smooth starts and stops, higher travel speeds for supertall buildings, twin cars on one mast, automatic landing controls and remote monitoring.

How a Construction Hoist Works

Base enclosure. A fenced enclosure at ground level with gates, protecting people from the descending car and holding the buffers.
Mast. A lattice steel mast built from sections, typically 1.5 m long, with a toothed rack along one side. The mast is fixed to the structure with ties at regular intervals.
Car. An enclosed cage or open platform carrying people and materials. Cars have doors or gates at the entry and landing sides and often a roof hatch used when erecting the mast.
Drive units. Electric motors with gearboxes drive pinions that engage the rack. Many modern hoists use frequency converters for smooth acceleration and accurate stopping at floors.
Safety device. An overspeed safety device, often called a safety gear, brakes the car on the rack if it travels too fast, independently of the drive brakes.
Landing gates. Gates at each floor, interlocked with the car so that they can only open when the car is at that level.
Power supply. Power comes through a trailing cable guided by a cable guide or, on very tall installations, through conductor rails.
Controls. The car is operated from inside by a trained operator or, on many modern hoists, with automatic call controls at the landings.

Types of Construction Hoists

Passenger and Material Hoists

The most common type, carrying both people and goods in an enclosed car. Single-car or twin-car versions, with two cars running on opposite sides of the same mast, increase capacity on large sites.

Material-Only Hoists

Hoists that carry goods only, with no people allowed on the platform. They range from small rack and pinion or rope hoists for low-rise work to heavy material hoists for industrial projects.

Transport Platforms

Open platforms that carry materials and, under specific rules, a limited number of people. They are common on renovation and facade projects and are often combined with mast climbing work platforms.

High-Speed Hoists

Hoists with faster drive systems, used on tall and supertall buildings to reduce travel time for large workforces.

Inclined and Special Hoists

Hoists running on inclined masts, for example on sloping structures, dam walls or chimneys, and custom hoists for shafts, towers and industrial plants.

Rope-Driven Hoists

Hoists driven by a winch and wire rope. They are common for materials in some markets and for specific applications, but less common than rack and pinion for carrying people.

Size Classes

Class	Typical payload	Typical speed	Typical use
Light material hoists and platforms	about 200 to 1,500 kg	slow	Low-rise and renovation work
Standard passenger and material	about 1,500 to 3,000 kg	about 0.5 to 1 m/s	Residential and commercial buildings
Heavy duty	about 3,000 kg and more	about 0.5 to 1 m/s	Industrial and large building projects
High speed	about 1,500 to 3,000 kg	above 1 m/s	Tall and supertall buildings

Figures are indicative and vary by manufacturer and configuration.

Main Manufacturers

Alimak, the Swedish company that is one of the best-known names in rack and pinion hoists.
GEDA, a German manufacturer of construction hoists and transport platforms.
Scanclimber, a Finnish maker of hoists and mast climbing work platforms.
STROS, a Czech manufacturer of construction hoists and platforms.
Zoomlion and other Chinese manufacturers, which supply large numbers of hoists to the domestic and export markets.

Main Uses

Moving workers and materials on high-rise residential and commercial buildings.
Fit-out logistics for facades, finishes and building services.
Access on chimneys, silos, cooling towers and wind turbine towers.
Industrial plants, refineries and power stations.
Bridges, dams and other civil structures.
Shipyards and offshore structures.

Planning a Hoist Installation

Size the system to the workforce. Estimate peak demand at shift start, lunch and end of shift, and choose the number of cars, payload and speed to match.
Choose the location early. The hoist needs a stable base, access for deliveries at ground level and a line up the building where landings can be formed on every floor.
Design the ties. Mast ties must be anchored to the structure at the spacing specified by the manufacturer, and the structure must be able to take the loads.
Plan landings and gates. Each floor needs a safe landing platform and an interlocked gate. The facade must be completed around the hoist position at the end of the job.
Consider the car size. Long or bulky items such as plasterboard, glass and pipes may need a larger car or a car with an extension or roof opening.
Plan dismantling. Removing the hoist and closing the facade opening must be included in the programme.

Safety

Construction hoists must be installed, inspected and tested by competent people in line with the manufacturer’s instructions and local regulations. Key controls include regular inspection of the mast, rack, pinions and ties, testing of the overspeed safety device, working gate interlocks at every landing and the base enclosure, and never exceeding the rated load or the number of passengers. Materials must be secured in the car. Wind speed limits apply, especially during erection and dismantling. Operators and users need training, and emergency procedures should cover the rescue of people from a stalled car. In Europe, requirements for builders’ hoists are set out in harmonised standards such as EN 12159 for hoists carrying persons and materials.

Trends and Technology

Modern hoists increasingly offer automatic call controls, load weighing, destination control and remote monitoring of usage, faults and maintenance. Energy-efficient drives, including regenerative systems, reduce power demand. Some sites integrate hoist data with access control and logistics planning to manage peaks in demand. High-speed hoists and twin-car arrangements are evolving for tall buildings, and in some projects permanent building lifts are brought into use early during construction to supplement external hoists.

Key Terms

Rack and pinion: a drive in which a motor-driven gear (pinion) climbs a toothed rack on the mast.
Mast tie: a bracket that anchors the mast to the structure.
Safety gear: an overspeed device that stops the car independently of the drive brakes.
Landing gate: a gate at each floor interlocked with the hoist car.
Twin-car hoist: two cars running independently on one mast.
Transport platform: an open hoist platform mainly for materials.

Frequently Asked Questions

What is the difference between a construction hoist and a mast climbing work platform? A construction hoist carries people and materials between floors. A mast climbing work platform is a working platform that moves along the facade so that people can work on it at height.

How tall can a construction hoist go? Rack and pinion hoists can be built to very great heights, and they are used on many of the world’s tallest buildings. The practical height depends on the model, ties, power supply and speed.

Does a construction hoist need an operator? Traditionally a trained operator ran the car. Many modern hoists have automatic controls that allow trained users to call and send the car, depending on local rules.

Can a construction hoist carry heavy materials? Yes, within its rated load. Heavy-duty hoists carry several tonnes, but very heavy or bulky items are usually lifted by crane.