Sargassum Eco Lumber
Turning harmful seaweed blooms into sustainable building materials
By Nick Owens
Summary:
Runoff from agricultural fertilizers has triggered massive blooms of Sargassum seaweed across the Atlantic Ocean.
These plastic-entangled mats wash up on coastlines, disrupting ecosystems, damaging infrastructure, and threatening the livelihoods of coastal communities.
Florida-based startup Sargassum Eco Lumber, founded by a father-daughter duo, has developed a method to collect this invasive seaweed—along with the plastic it traps—and convert it into a durable and versatile building material.
Their model not only addresses two major environmental challenges in the form of Sargassum and plastic pollution, but also offers a sustainable alternative to traditional building materials, which are typically energy- and emissions-intensive.
The world’s addiction to plastic means we now produce 430 million tons of it each year. Half of this is designed for single use—discarded almost immediately. Unsurprisingly, a staggering 85% of this plastic never reaches recycling facilities. Instead, it ends up in landfills, unregulated waste sites, or polluting our oceans and ecosystems.
Simultaneously, nutrient runoff from industrial agriculture—particularly nitrogen and phosphorus—has fuelled massive seaweed blooms across the Atlantic. These vast mats of Sargassum now form what’s known as the Great Atlantic Sargassum Belt, visible from space and estimated to weigh 24.2 million tons.
On land, Sargassum piles up on beaches without warning, where it rots, releasing hydrogen sulphide—a gas with an unpleasant odour and potential health risks like headaches and eye irritation. In the ocean, it entangles with plastic debris and disrupts coastal ecosystems: blocking sunlight, harming marine life, and preventing sea turtle hatchlings from reaching the water. It can also interfere with infrastructure and tourism, particularly in regions like the Caribbean where seasonal income is vital.
So—what can be done with all this plastic and invasive seaweed?
Looking to address both problems at once, father-daughter team Andrés de Antonio Simancas and Raquel de Antonio Crespo founded Sargassum Eco Lumber. Based in Miami, where Sargassum cleanup costs the city an estimated $4–6 million annually, the duo set out to turn the nuisance into something useful. Andrés, a serial inventor, began experimenting with ways to repurpose Sargassum and eventually developed a method to convert it—together with discarded plastic—into a viable building material.
After multiple iterations, the result is Eco Lumber: a durable blend of processed seaweed and plastic that forms robust planks and panels. To make it, Sargassum is collected from beaches or the sea using trucks, shovels, and tractors. It’s then dried at high temperatures and ground down. Meanwhile, plastic waste—such as shopping bags and packaging—is densified and shredded. The two materials are combined and moulded into synthetic wood sheets.
This new material is strong, durable, and resistant to rot, termites, and rust. It's a cost-effective alternative to plywood and represents a sustainable solution to two pressing environmental problems. Because it’s made entirely from waste, it appeals to industries and consumers looking for environmentally friendly building options.
Sargassum Eco Lumber is still in its early production phase and currently raising funds to scale. Despite this, their innovative panels—already shown to outperform traditional plywood in strength—have drawn interest from logistics and pallet companies committed to reaching carbon neutrality by 2040–2050.
Earlier this year, the company showcased its prototype at JEC World in Paris, the premier global composites expo, where it represented the United States. With potential applications in construction, maritime industries, and beyond, Eco Lumber offers a promising alternative to conventional materials. Using freely sourced waste reduces production costs while tackling two major environmental challenges.
By 2050, the company estimates it could help cut 21 million tons of CO₂ emissions from the construction sector—a significant stride toward sustainability. Sargassum Eco Lumber proves that with creativity and commitment, today’s waste can become tomorrow’s solution.