Cocoon Carbon Closes $15M Series A to Plug the Green Cement Supply Gap

Key Takeaways

1. $15M Series A closed by UK-based Cocoon Carbon, co-led by 2150 and Brick & Mortar Ventures, with participation from The Venture Collective (TVC) and existing backers​
2. LoopCem, a cement replacement derived from electric arc furnace (EAF) steel slag that reduces concrete’s embodied CO2 by up to 40%​
3. Cocoon plans to deploy its technology across more than 50 steel plant sites in the U.S. and Europe​
4. SCM demand growing 6-7% per year, while traditional coal-plant and blast furnace supply continues to shrink, creating a structural deficit the company aims to fill​

Quick Recap

London-based construction materials startup Cocoon Carbon has officially closed a $15 million Series A funding round, as announced on March 17-18, 2026, and reported by EU Startups, Axios, and SOSV. The round was co-led by climate-tech-focused investors 2150 and Brick & Mortar Ventures, with participation from The Venture Collective and continued backing from existing investors Wireframe Ventures, Celsius Industries, Gigascale Capital, and SOSV. The capital will go toward deploying the company’s first commercial demonstration facility in the United States and scaling its team on both sides of the Atlantic.

Technology and the Capital Strategy

LoopCem: Turning Steel Waste Into Cement Gold

Cocoon Carbon’s core product, LoopCem, is a Supplementary Cementitious Material (SCM) engineered from the slag byproduct of electric arc furnaces (EAFs). The innovation sits at a critical industrial intersection: as the steel sector shifts from coal-powered blast furnaces to cleaner EAFs (which already account for 70% of steel production in the U.S.), it generates a new type of “e-slag” that cannot directly substitute for traditional blast furnace slag used in concrete.

Cocoon’s process solves this with rapid cooling technology that captures molten EAF slag directly out of production and cools it roughly 100 times faster than existing methods, transforming it into a consistent, high-performance SCM. The resulting material performs comparably to traditional SCMs at a 30% cement replacement ratio and meets standard industry benchmarks for strength and durability. Third-party validation of the material in concrete applications has already been completed, and the technology has been piloted at a major steel mill.

How the $15M Will Be Deployed?

The Series A capital has a clear three-track deployment plan:

• First U.S. commercial demonstration facility: The primary use of proceeds, intended to validate Cocoon’s process at industrial scale in a key target market
• Team expansion: Hiring process engineers, materials scientists, and commercial staff in the UK, alongside plant operators and technical personnel in the U.S.
• Scale roadmap: Building an operating track record that enables a rollout across more than 50 steel plants in the U.S. and Europe by 2035

CEO and Co-Founder Eliot Brooks described the market opportunity plainly: “The SCM market is facing a structural deficit at exactly the moment infrastructure demand is rising. We’re focused on delivering a plug-and-play solution that gives concrete producers access to affordable, local materials while improving the economics of electric steelmaking.”​

This round follows Cocoon’s $5.4 million pre-seed in August 2024, which was used to build an R&D facility and concrete testing lab in London and initiate pilot-phase testing at a steel plant in northern England.

Why This Funding Round Arrives at a Critical Moment?

The Structural SCM Shortage Nobody Is Talking About

For decades, the concrete industry relied on two cheap, abundant sources of SCMs: fly ash from coal-fired power plants and slag from traditional blast furnace steel production. Both of those supply streams are now in permanent decline. As the world decarbonizes energy generation and steel production, this byproduct supply is drying up.​

The global SCM market was valued at approximately $16.5 billion in 2025 and is projected to reach $28.8 billion by 2033, growing at a CAGR of 7.2%. Demand for SCMs is running at 6-7% annual growth, but supply has not kept pace, already triggering price increases in multiple markets. Cocoon Carbon is positioning itself to fill exactly this gap, using the EAF steel industry’s growing output as its feedstock.

Regulatory Tailwinds and Infrastructure Spending

Green building codes, embodied carbon regulations in the EU, and the U.S. Inflation Reduction Act’s clean manufacturing incentives are pushing concrete producers to actively seek low-carbon inputs. At the same time, infrastructure demand in both the U.S. and Europe is rising sharply, putting pressure on construction material supply chains. Cocoon’s low-capex, co-located model (building at steel plants rather than standalone facilities) positions it to respond to this demand faster than competitors requiring new greenfield infrastructure.

Competitive Landscape

Cocoon Carbon is not alone in targeting cement’s carbon footprint, but its specific niche (EAF slag conversion to SCMs) differentiates it from companies reinventing Portland cement production entirely. The two most directly comparable startups operating in the low-carbon SCM and cement alternative space are Material Evolution (UK) and Fortera (US).

Strategic Analysis
Cocoon Carbon has a distinct structural advantage: its technology does not require new production sites, which removes a major capital barrier and speeds up deployment timelines. Fortera, by contrast, leads the competitive set on total capital raised and commercial production proof points, with an operational plant already selling into real-world projects. Material Evolution holds an edge in raw decarbonization depth (85% CO2 reduction), while Cocoon Carbon and Fortera both target the more pragmatic “drop-in” replacement positioning that concrete producers prefer for a seamless supply transition.

Bayelsa Watch’s Takeaway

I have watched the green building materials space closely for a while now, and I think this Cocoon Carbon round is genuinely one of the more interesting climate investments of early 2026. Here is why: most cement decarbonization plays require you to change the production process at the cement plant itself, which means convincing a very conservative industry to retrofit or replace infrastructure it has been running for decades. Cocoon sidesteps that problem entirely by plugging into steel mills, where plant operators are already looking for ways to monetize their waste stream.

In my view, this is a bullish signal not just for Cocoon Carbon, but for the entire SCM supply ecosystem. The market gap is real. The regulatory and infrastructure spending tailwinds are real. And a $15M round to build a first commercial U.S. facility is a credible next step for a company that has already cleared the third-party validation hurdle. I generally prefer climate startups that solve two industry problems at once, and Cocoon does exactly that: it gives steel producers a revenue stream from waste and gives concrete producers a local, affordable, low-carbon material. That dual-sided value proposition is a rare thing to find at Series A.