Monumental just closed a $32 million Series B led by Khosla Ventures, roughly two years after a $25 million round that CEO Salar al Khafaji describes as “basically still an R&D round.” The difference this time: 150+ robots in the field, brickwork delivered on more than 100 homes, and pricing that matches local masonry rates. We sat down with Salar to unpack what changed, why earlier bricklaying robots stalled, and where the money goes.
Two years ago, we visited Monumental in Amsterdam shortly after its $25 million raise. Back then, the pitch rested on prototypes and small-scale demos. Promising, sure, but still a bet on what the robots might do rather than what they had done.
This week, the company announced a $32 million Series B, and the pitch looks nothing like it did in 2024. Khosla Ventures led the round, with existing investors Plural and Hummingbird returning. The company now runs a fleet of more than 150 robots that have delivered brickwork for over 100 homes, plus a school, a community centre, a hotel, and hundreds of metres of Amsterdam’s canal walls.
On the latest episode of Bricks & Bytes, Salar walked us through the gap between those two rounds. His answer was blunt: the Series B was “raised off actual success.” Here is what that looks like up close.
From R&D Round to Proof Round
What Monumental had to show between 2024 and 2026
Salar draws a clean line between the two raises. The 2024 round funded research: prototypes, demos, small-scale wins. The Series B was underwritten by delivered work. When investors did diligence this time, they called customers. “VCs want to have customer references. They call the customers, they hear great stories,” he told us.
The delivery numbers back that up. Beyond the 100+ homes, the robots have completed brickwork for a school, a sports centre, commercial units, and hundreds of metres of canal walls. And the curve is steepening: nearly half of those homes were completed in the past three months alone.
Deployment breadth matters too. At the time of recording, Salar said robots were running on four commercial sites simultaneously, putting Monumental in a tiny club. Commercially deployed robotics companies at multi-site scale can, as he put it, probably be counted on two hands.
Why the Last Generation of Bricklaying Robots Stalled
Timing first, business model second
Bricklaying automation has a graveyard. The SAM semi-automated mason appeared roughly a decade ago, and Australia’s FBR built the truck-mounted Hadrian X, a machine that, at nearly $6 million per unit, asked contractors to make a massive upfront bet on unproven technology.
Salar’s diagnosis starts with timing. Everything Monumental’s robots do depends on modern computer vision and localization, a stack that simply did not exist for earlier players. His comparison: asking why there were no self-driving cars in the 1980s. The compute was not there. It could not have been done.
Then comes the part he thinks matters even more, the go-to-market. General contractors do not want to buy unproven equipment, and in his view they should not have to. What they do every day is subcontract work and manage those subcontracts. So Monumental made itself look like the thing contractors already know how to hire: an autonomous subcontractor that bids for brickwork and gets paid for finished walls.
What an Autonomous Subcontractor Actually Does On Site
Day zero runs through Atrium, not a sales deck
The process starts before any robot arrives. Monumental scopes every project first, and with more demand than capacity, Salar says the company happily turns down work that does not fit. A heritage job full of decorative arches gets a polite no.
If the answer is yes, the drawings go into Atrium, Monumental’s proprietary orchestration software. The customer gets a 3D model of the site, an exact brick count, precise mortar quantities, and a full build plan. On day one, the team places localization stickers, runs a camera mapping pass, and the robots start laying. Only Monumental’s own trained operators go near the machines while they run. Want a selfie? The robot gets emergency-stopped first.
The service wrapper carries a real guarantee. Monumental agrees a scope of work, and if the robots cannot finish it, human crews step in at the company’s own expense. The customer never holds the technology risk.
We’re not promising to deliver you a robot. I’m promising you 5,000 bricks at that price, in that time period, at some quality level.
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Join 3000+ ReadersSalar goes deeper on all of this in the full episode, including the site anecdotes that did not make it into this write-up. Worth the watch:
The Economics: Priced Like a Masonry Gang
Comparable rates, with autonomy carrying the margin
Monumental quotes the way any brickwork subcontractor does: per thousand bricks, per square metre, whatever the local convention is. And the prices land very close to local market rates. The margin story sits underneath. When autonomy is high, the robots make money at those rates. When autonomy is low, Monumental absorbs the cost rather than shifting risk to the customer. Salar sees that as exactly what a technology company should be doing.
On speed, he is refreshingly unbothered. A single set of robots averages between half and two-thirds of what a human mason lays, with peak days running double or triple that. The robots are compact, though, so the real answer to any deadline is fleet size. Need the wall twice as fast? Deploy twice as many robots. Quoted timelines are deliberately conservative so delivery always lands on schedule.
Where the $32 Million Goes
UK scale-up, US pilots, and a widening scope of work
The UK is the main focus for the next six months. Monumental already has customers, a local team, and corporate-level support from VINCI, with delivery happening at business unit level through firms like Taylor Woodrow, as Salar described it. The market need is stark: to hit the UK government’s 1.5 million homes target, the Home Builders Federation estimates the country needs at least 20,000 more bricklayers, yet only around 1,990 completed apprenticeships in 2024.
The US gets its first pilots this year, starting in a couple of states while the company figures out the right deployment model for a market that dwarfs the Netherlands. The labor math is just as sharp there: the company points to US home builders needing 2.2 million additional workers over the next three years.
The scope of work keeps widening too, driven by forward-deployed engineers, a model Salar carried over from Palantir, which acquired his previous startup Silk in 2016. Engineers work on live sites and program new capabilities as real-world quirks appear. Two years ago the robots only laid straight walls on the ground. Today: corners, deep reveals, curved walls, scaffolds, mast climbers, even integrated bat boxes. The ten-year vision is a broad autonomous subcontractor covering the full facade, with Atrium potentially opening up as an orchestration layer for other companies’ robots.
The Two Rounds, Side by Side
A quick-reference view of what changed
| 2024 Round | 2026 Series B | |
|---|---|---|
| Amount | $25 million | $32 million |
| Lead investors | Co-led by Plural and Hummingbird | Khosla Ventures, with Plural and Hummingbird participating |
| Raised on | Prototypes and small-scale demos, per Salar | 100+ homes of delivered brickwork, canal walls, commercial buildings |
| Deployment status | R&D phase | 150+ robots on live commercial sites in the Netherlands and UK |
| Next milestone | Prove commercial delivery | UK scale-up and first US pilots |
Monumental raised $32 million in a Series B led by Khosla Ventures, with participation from existing investors Plural and Hummingbird. The round was announced in mid-July 2026 and follows a $25 million raise co-led by Plural and Hummingbird in February 2024. (Source)
The company’s robots have delivered brickwork for more than 100 homes, a school, a community centre, a sports centre, a hotel, commercial units, and hundreds of metres of Amsterdam’s canal walls. Nearly half of the completed homes were finished in the three months before the Series B announcement. (Source)
Monumental operates as an autonomous subcontractor. Contractors never buy or rent the robots. Instead, the company bids for brickwork like any specialist trade and gets paid for finished walls at rates comparable to local masonry pricing. If the robots fall short on an agreed scope, human crews complete the work at Monumental’s own expense, so the customer never carries the technology risk. (Source)
On the episode, Salar said a single set of robots averages between half and two-thirds of a human mason’s output, with peak days reaching double or triple that. Because the robots are compact and deployed in fleets, headline speed matters less than fleet size: doubling the number of robots on site doubles throughput. The company deliberately quotes conservative timelines so it can always deliver on schedule. (Source)
Two reasons, according to Salar. First, timing: the modern computer vision and localization stack the robots depend on did not exist a decade ago. Second, the business model: FBR’s Hadrian X cost nearly $6 million per machine, forcing contractors to make a huge upfront bet on unproven technology, which runs against how the industry actually buys. Monumental sidesteps both by selling finished walls rather than machines. (Source)
The UK is the primary commercial focus for the next six months, with an existing local team and live customers. The company is also launching its first US pilots this year in a small number of states, while it works out the right deployment and logistics model for the American market. It is hiring commercial roles in the US and robot operators in the UK. (Source)
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