Dutch bricklaying robot startup raises $32m from Khosla to expand across Europe/US

Amsterdam-based construction robotics company Monumental has raised a $32 million Series B led by Silicon Valley’s Khosla Ventures to expand its fleet of autonomous bricklaying robots across Europe, deepen its UK presence and launch in the US.

Existing European investors Plural and Hummingbird also participated in the round.

Founded in 2021, Monumental has built a fleet of more than 150 robots and says its machines have constructed walls for more than 100 homes, as well as a school, hotel, community centre and canal infrastructure in the Netherlands and the UK.

Between 50 and 100 robots are deployed across construction sites on a typical day, co-founder and chief executive Salar al Khafaji told Pathfounders over a call.

“It’s a very hyped space, with a lot of demo-ware and almost nothing to show for it,” he said. “We have, on an average day, anywhere between 50 and towards 100 robots deployed right now, all across multiple construction sites.”

Nearly half of the homes completed using Monumental’s robots were built during the past three months, compared with eight in the previous quarter, according to the company.

Monumental has a fairly unique model. It does not sell or lease its machines to construction companies. Instead, it operates like an ‘autonomous subcontractor’, charging construction companies only for completed walls and assuming the cost and technical risk of operating the robots.

“Our customer is just subcontracting to us,” al Khafaji said. “They’re paying for the wall that’s being delivered. If I don’t deliver anything, you don’t pay me anything.”

The model allows for very low friction in terms of GTM. Contractors can adopt robotic construction without buying equipment, training specialist teams or accepting the risk that the technology might not perform as expected.

Al Khafaji compared the approach with Waymo’s robotaxi service, where customers pay for a journey rather than buying an autonomous vehicle or concerning themselves with how much of the driving is automated.

“It shifts all the risk from the customer to us,” he said. “Construction contractors are very comfortable with this model.”

It also allows Monumental to deploy machines before every part of the system is fully autonomous, using operators, remote assistance and human intervention to fill gaps while the technology improves.

Monumental’s system uses several specialised robots rather than a single humanoid machine.

Two crane-like robots carry out the masonry work, with one positioning bricks and another applying mortar. Additional robots transport bricks and mortar to the machines constructing the wall.

“You’re not going to solve this problem by having a humanoid walk around with a wheelbarrow,” al Khafaji said. “That’s probably not the form factor that will make construction autonomous.”

The robots use sensors, computer vision and positioning systems to lay bricks and mortar with millimetre precision. 

“We have designed and built our own hardware and robots, and we’ve designed and built our own software operating system,” al Khafaji said. “We call it Atrium.”

Atrium, Monumental’s physical AI software platform, was developed internally. Atrium ingests architectural drawings, determines where robots need to be positioned, coordinates their movements and manages localisation, quality control and remote operation.

al Khafaji argued that construction robotics requires more than placing a general-purpose AI model inside a machine, because the software must coordinate several physical systems on frequently changing, partially completed construction sites.

“You need to know what needs to be built and where the architect wants it,” he said. “If you have multiple robots, they need to be coordinated, synchronised and orchestrated.”

This fresh funding will be used to manufacture and deploy more robots, hire hardware and software engineers and expand into additional construction tasks.

Monumental currently focuses on brickwork but plans to move into blockwork, installation and complete building façades.

“There are basically three things we want to do with the money,” al Khafaji said. “We want to build more robots and deploy them… we want to do that in more countries, and we want to go from just brickwork to blockwork to building entire façades.”

The company estimates that bricklaying labour alone represents a market of around £5 billion a year in the UK and a similar amount in Germany.

Al Khafaji said Monumental’s underlying system could eventually automate between one-third and one-half of the work carried out on the main construction phase of a building, although it would not enter separate areas of construction such as excavation and ground preparation, which are still largely controlled by humans. 

Monumental recently appointed a UK country manager and is building a local team. It plans to expand its UK deployments and begin its first US projects this year.

The company is targeting an industry constrained by labour shortages and weak productivity growth.

The Home Builders Federation estimates that the UK needs at least 20,000 additional bricklayers to meet the government’s target of building 1.5 million homes. Around 1,990 bricklaying apprenticeships were completed in 2024, according to figures cited by Monumental.

Al Khafaji rejected the idea that the robots would simply replace existing workers, saying there’s already a dearth of them.

“We don’t replace bricklayers,” he said. “The unique thing about construction is that there’s a massive lack of labour in this industry. It is constrained by a lack of labour.”

A group of three Monumental robots can perform the work of roughly two brick masons at peak output, according to al Khafaji. Average productivity is currently slightly lower because of downtime and the need for human intervention, but he said the company has a path towards matching or doubling the productivity of a mason.

He added that the subcontracting model allows Monumental to increase output by deploying several robot groups on the same project rather than relying solely on making an individual machine faster.

“If you tell me as a contractor that you need to build four times as fast, I will deploy four times as many robots,” he said. “It’s actually not about speed. It’s more about economics.”

al Khafaji said construction productivity has increased by only roughly 10% since 1945, compared with an eightfold increase in manufacturing productivity.

“Construction costs have exploded while the industry itself has barely changed in decades,” said Khosla Ventures founder Vinod Khosla in a statement. “Monumental is solving this by bringing robotics into the physical world, and the proof is already standing.”

Monumental was founded by al Khafaji and chief technology officer Sebastiaan Visser. The pair previously founded data visualisation company Silk, which Palantir ‘acqui-hired’ in 2016.

Ironically, Monumental has ended up applying a version of Palantir’s forward-deployed engineering model to construction, putting Monumental’s engineers and robots directly onto customer sites rather than developing machinery in isolation and handing it over to contractors.

Al Khafaji claims he does not believe Monumental currently has a close competitor operating at a similar deployment scale in automated brick and block construction.

But perhaps the most direct UK comparison might be Construction Automation, which has developed the Automated Bricklaying Robot, or ABLR. This track-mounted system works with conventional bricks, blocks and mortar and has secured NHBC acceptance. However, the company still describes itself as working with housebuilders and supply-chain partners to bring the system to the wider market.

Also, while US-based Construction Robotics pioneered the SAM100 semi-automated bricklaying machine, its current business is centred on MULE material-handling systems that help construction workers lift and position heavy blocks, making it primarily a labour-assistance company rather than an autonomous subcontractor.

In the US, better-funded construction robotics companies, including Built Robotics, Bedrock Robotics and TerraFirma, are concentrating mainly on earthworks, excavation and infrastructure preparation.