Construction robot startup Monumental reels in $32M

Monumental BV, a Dutch startup that operates a fleet of bricklaying robots, has raised $35 million in funding. 

Khosla Ventures led the Series B investment. Monumental stated in its funding announcement today that existing backers Plural and Hummingbird chipped in as well.

Monumental uses robots to construct the walls of homes, schools and other buildings. It uses two robots called Petra and Panama to deliver bricks and mortar, respectively, to the section of a construction site where they’re needed. A third system called Pisa carries out the bricklaying work.

“Every robot we deploy expands the industry’s capacity to build, bringing a future of beautiful, affordable, bespoke buildings and infrastructure closer to reality,” said Monumental co-founder and Chief Executive Officer Salar al Khafaji (pictured, left, with co-founder Sebastiaan Visser).

The company coordinates its robots using a platform called Atrium. According to Monumental, the software also automates several of the other tasks involved in construction projects.

Atrium automatically generates blueprints based on high-level details inputted by an architect. Users can customize parameters such as the manner in which bricks should be arranged. Most construction projects use bricks that lie on their longer side. Atrium can also place bricks vertically, an arrangement that is mainly used for decorative purposes.

The first version of a building facade plan often contains inaccuracies that can complicate construction. Monumental corrects errors using a method called photogrammetry. The company takes photos of a construction site, assembles them into a three-dimensional virtual replica and compares the replica to the blueprints. Monumental says that it can catch millimeter-scale inconsistencies.

Once a blueprint is ready, Atrium translates it into a bricklaying plan for the company’s robots. The software then uses sensor data from the robots to monitor for mistakes. Atrium can coordinate multiple robot teams on the same site, which makes it possible to speed up construction by parallelizing work.

Monumental developed a custom programming language for Atrium. The syntax, which is known as Plan, enables the company’s developers to optimize how the company’s robots should go about their work. Software teams only have to provide a relatively high-level description of the project workflow. The more granular details are defined automatically by a component called an interpreter.

Monumental had to solve multiple technical issues to make its robots work reliably. 

Robot sensors sometimes malfunction, which means that the data they generate doesn’t reflect the parameters of a construction site. Monumental avoids such issues by calibrating its sensors before each project. The calibration is carried out at a dedicated section of the company’s headquarters that is equipped with motion cameras.

Monumental’s robots pick up the bricks they use one by one. If a robot picks up a brick a few millimeters off center, it may incorrectly place the brick in the building under construction. The company addressed the challenge by training a custom neural network that automatically offsets such errors. 

Monumental uses its robots to deliver a bricklaying service with outcome-based pricing. According to the company, its billing approach removes the need for construction firms to buy pricey machinery. The company has so far helped customers construct over 100 homes, schools and other buildings.

Monumental will use its new funding to hire more engineers. Additionally, the company plans to grow its international presence and the number of construction tasks that its robots can automate.

Photo: Monumental