Concrete Troweling Robot History and Where ABB Fits

Every concrete floor in a garage, warehouse or block of flats gets smoothed while the concrete is still soft. For most of the last century people did that with hand floats and trowels, and later by steering power trowels across the slab. A concrete troweling robot does the same job with powered trowels on a machine that drives itself or is steered remotely. This post covers how finishers worked by hand, the robots Japan's big builders sent across slabs in the 1980s, the troweling and screeding robots now at work in China and Singapore, and where ABB robots, which already drill into concrete and print it, could fit next.

Finishers on a new office floor slab in Camp Crook, South Dakota, in 2010: one runs a walk-behind power trowel while others work the edges by hand. Photo: Forest Service, Northern Region via Wikimedia Commons (public domain)

How finishers floated and troweled concrete by hand

A concrete finisher's work follows a fixed order. Concrete comes off a chute, out of a pump or from a wheelbarrow, gets spread with shovels and rakes, and is leveled by pulling a straightedge back and forth across the forms. That step is called screeding. Next the finisher smooths the surface with a hand trowel, a long-handled bull float or a powered float, and runs an edger along the sides so the edges are less likely to chip. In a photo from May 1938, a worker kneels on a fresh slab to finish a garage floor at the Main Dam works in Belchertown, Massachusetts.

A worker kneels on the wet slab while the east garage floor of the Main Dam administration buildings in Belchertown, Massachusetts, is finished, 12 May 1938. Photo: Stuart D. Pike, Massachusetts Metropolitan District Water Supply Commission via Wikimedia Commons (public domain)

Then came the power trowel, also called a power float or troweling machine, which does the jobs of a hand trowel, hand float, darby and concrete float. Walk-behind models are guided by an operator on foot. Ride-on models have two rotor assemblies and a seat, and the driver steers with two levers or joysticks; they run from 1.8 m machines of 270 to 320 kg up to 3.7 m machines of more than 910 kg. The machines still need people. A 2010 photo from a Forest Service office build in Camp Crook, South Dakota, shows one worker running a walk-behind trowel while two others kneel at the slab edges with hand tools.

A two-rotor ride-on concrete trowel made by Dynamic, with the driver's seat on top. Photo: DIMEX / Wikimedia Commons (CC BY-SA 4.0)

The first robots came from Japan. In May and June 1985, James Albus of the US National Bureau of Standards toured six of Japan's largest construction firms and wrote a trip report. Takenaka had developed a placing and finishing system. A small walking bulldozer leveled the concrete with a blade whose height a laser controlled, and a tracked robot with automatic navigation smoothed it with eight rotary trowels that swept all the way around the vehicle. The latest version finished 300 square meters an hour, the work of three people, and set its trowel pressure to suit the hardness of the concrete. Kajima and Shimizu built trowel robots too: Kajima's Mark II and Shimizu's round, remote-controlled Flat-Kun.

A technician levels and finishes concrete with a laser screed at the Silo 3 Interim Storage Area, a US Department of Energy site. Photo: US Department of Energy via Wikimedia Commons (public domain)

Troweling and screeding robots on building sites today

In China, Bright Dream Robotics, founded in Foshan in July 2018, says it is developing 45 construction robots, among them a basement concrete trowelling robot. Its concrete combo pairs a concrete filling robot with robots that level and smooth the floor, and the company says the combo cuts a concrete crew from 12 people to 8. By the end of September 2022 it reported more than 1,600 robots delivered to over 600 projects in 30 provinces. In the United States, Built Robotics, best known for its autonomous excavator system, bought the Y Combinator-backed startup Roin Technologies in January 2023. TechCrunch said Roin was best known for concrete robots that trowel and spray shotcrete.

Built Robotics' Exosystem hardware installed on a Komatsu excavator, 2021. Built bought the concrete robot startup Roin Technologies in 2023. Photo: Carolinah13 / Wikimedia Commons (CC BY-SA 4.0)

The latest news comes from Singapore. On 25 September 2026 Chee Hong Tat, the Minister for National Development, said the Housing and Development Board would use screeding robots at more Build-to-Order sites. CNA described one in a new four-room flat. A robot no bigger than a dishwasher zigzagged across the living room, guided by a laser, leveling and smoothing fresh screed, while in another room a worker set out level pegs by hand. A worker can learn to run the robot in a few days, where the manual job takes months of practice, and it screeds a four-room flat in about a day. "A screeding robot automates much of this process and creates a more consistent finish," Chee said.

HDB blocks of the Kallang Horizon estate in Singapore under construction, February 2024. Photo: S5A-0043 / Wikimedia Commons (Attribution)

ABB does not make a troweling robot, and we found no ABB troweling project. ABB arms do already work on concrete. Schindler's robotic elevator installation system, developed with ETH Zurich and ABB Robotics in Switzerland, carries an ABB IRB 2600 with a 1.65 m reach and a 29 kg payload up a concrete elevator shaft, and the robot scans the wall for hidden rebar or an uneven surface before it drills anchor holes. In Japan, Serendix used an ABB IRB 6700 in its factory to 3D print the main structural elements of a new station building at Hatsushima for JR West. Builders then installed the building in a single night.

Schindler's R.I.S.E platform hanging in a concrete elevator shaft, with its ABB IRB 2600 arm mounted on the frame. Photo: ABB

Where concrete troweling robots go from here

I expect homeowners to meet these robots first in new flats and houses. Chee has asked HDB to work towards using screeding robots and smart hoists at all new BTO sites, and HDB will extend its screeding trials to at least four more projects in 2027. In 2021 the Tokyo contractor Floor Agent built Revive Robo, a 126 kg battery robot that levels and compacts a concrete floor at the press of a button; on 1,000 square meters it cut the work from 10 or 11 worker-days to 6 or 7. Factories are the other route. Serendix printed its station parts indoors, and Mr. Masueda of JR West said that doing the structural work in a factory let them significantly shorten the schedule on site.

Concrete elements printed by Serendix in its factory, with the ABB IRB 6700 robot behind them. Photo: ABB

ABB robots could possibly take on parts of this work. Takenaka's 1985 robot already matched its trowel pressure to the hardness of the concrete. Polishing is a similar contact job, and ABB lists polishing among the jobs of its IRB 1300. A GoFa cobot is built to work alongside people, with force and speed limits, and reaches up to 1.62 m. On a mobile base, one could work the edges and corners that finishers still do by hand. Precast factories, where the slab comes to the robot, look like the easier place to start. Paths like these are usually built and tested in RobotStudio before a robot touches wet concrete.

Moving an ABB GoFa cobot arm by hand. Photo: ABB

Cost, safety and skills are the open problems. HDB expects robotics to cost slightly more at first and to get cheaper with wider adoption. On safety, Occupational Health and Safety reported in October 2026 on a NIOSH bulletin: building sites change as a project goes on, dust, uneven ground, weather and poor lighting can confuse robot sensors, and firms should run task-specific risk assessments and track near misses and emergency stops. On skills, Monolith Corporation, a Japanese concrete floor contractor, wrote in 2023 that plasterers and slab finishers had fallen to a tenth of their numbers in the high-growth years. In ABB's 2021 survey of 1,900 construction firms, 44 percent said they struggle to recruit.

Petty Officer Selina Rodriguez of Naval Mobile Construction Battalion 7 finishes concrete with a bull float at Kandahar Airfield, February 2012. Photo: Chief Petty Officer Yan Kennon, U.S. Navy via Wikimedia Commons (public domain)

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