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In 2015, at Cannacosta, a cannabis and hemp conference she and her husband organized in Costa Rica, Ashley Javogue watched a presenter demonstrate hempcrete and had a small, useful heresy. The plant based wall system everyone was praising for keeping European and North American homes warm should, run in reverse, keep tropical homes cool.
A decade later, the company she co founded, Zegreenlab Construction, has completed more than 35 hempcrete style projects across Costa Rica. The quiet twist is that most of those walls contain no hemp at all. They are built from bagasse, the fibrous pulp left over after Costa Rica’s sugar mills crush their cane.
Zegreenlab calls the finished product bagacrete. It may be one of the clearest working examples of what a hemp building movement looks like once it stops importing containers and starts building with what is already on the ground.
From cannabis reform to construction
Ashley and her husband, Emmanuel, began working in the cannabis and hemp space around 2014, focused on reforming Costa Rica’s laws. He moved toward CBD oils and finished products. She was pulled toward the construction side.
The turning point was a workshop with British hempcrete pioneer Steve Allin. Zegreenlab brought Allin back to Costa Rica for a workshop of their own, imported hemp hurd, and taught their first hempcrete class in April, 2017. It became clear quickly that growing hemp in Costa Rica’s climate would be difficult, and shipping hurd by the container was not a long term answer.
Because Ashley’s husband is French, they had connections in France. At the 2016 International Hemp Building Association symposium, they met researchers at the University of Lyon who had spent decades studying hempcrete and were already testing alternative agricultural fibers, from sunflower stalks to typha fibers sourced in Senegal. Zegreenlab shipped them a container of Costa Rican bagasse and asked what it could do.
Why bagasse
Costa Rica has a large sugar industry, and three big mills sit near Zegreenlab’s facility. During harvest, those mills produce bagasse by the ton. Some of it is burned for electricity, and a great deal is still available. The Lyon team ran their tests and reported that it worked very well.
“It has basically the same properties. We call it bagacrete, from the word bagasse. It provides insulation, is fire resistant, lightweight, and nontoxic. We use lime as the binder, just as you would with hempcrete. The only thing that changes is the plant based aggregate.”Ashley Javogue, Zegreenlab
Zegreenlab has also evaluated coffee husks, rice husks, teak shavings, and abacá, a plant fiber similar to banana. Some of those may show up in specialty products like ceiling panels. Bagasse has one practical advantage the others do not always match. It is available by the ton, at a workable price, from suppliers a short drive away.
Bagacrete is not a load-bearing material, and Ashley is direct about that. Zegreenlab manufactures it at roughly the same density as hempcrete, which keeps the wall light and full of small air pockets. Those pockets are what deliver thermal and acoustic insulation, humidity regulation, and breathability.
The team experimented with denser, structural mixes. It can be done by pushing in more lime, but that defeats the purpose. “The denser you make the material, the less insulating it becomes,” she said. Costa Rica also enforces a strict seismic building code because of frequent earthquakes, so structural performance is handled by a code compliant wood or steel frame. Studies elsewhere have shown that hempcrete style walls can offer bracing qualities, but local code treats the material as infill, and Zegreenlab designs to that reality.
Panels, blocks, and a wall system builders already understand
Zegreenlab makes two main prefabricated products. The panels behave somewhat like drywall. They screw onto a wood or steel stud and track frame, with roughly four panels covering the area of one sheet of drywall. The wall then receives a coarse plaster followed by a fine finishing plaster. A completed wall is about 16 centimeters thick, depending on the framing.
The blocks are 10 centimeters thick, joined with mortar, and set between wood or steel columns and beams. Some block designs include channels that accommodate posts, rebar, or reinforced columns inside the wall itself.
Both formats were designed to slot into construction methods Costa Rican builders already use, and that decision has paid off. After eight years of steady work, architects now specify Zegreenlab materials on their plans, and the company is in full production for the next four months.
Clients arrive from three directions. Sometimes a homeowner finds Zegreenlab first and brings in an architect. Sometimes an architect has a project in motion and wants to use the material. Sometimes a builder calls because the product is already in the drawings. In almost every case there is an educational conversation. “It is a wonderful and dependable material,” Ashley said, “but it must be used appropriately.”
Inside the production facility
Zegreenlab’s site is a working manufacturing shop that runs on local realities. On the day of the interview, production was paused because there was no water. The facility depends on the nearby village’s supply, and rural Costa Rica adjusts around that.
The process itself is straightforward. Bagasse is wetted, mixed with lime in a company designed mixer adapted from a lime mixer, poured into molds, and left to cure. Everything is made in house, including custom pieces like lamps and prototype tables. Lime comes from a local supplier.
Bagasse arrives in bulk and is sifted into four grades. Coarse fiber, with most of the dust removed, goes into panels and blocks. Medium fiber grades go into mortar and coarse plaster. The finest fibers and powder go into finishing plasters. The sifting system is low tech but effective, built around a rotating separator designed by a young engineer who works with the company.
Zegreenlab also produces natural lime plasters in a range of colors, textures, and grades. Pigments are natural iron oxides from a local supplier. The team has experimented with rice ash blended into lime, which, depending on how it is floated and finished, can produce a surface that reads almost like marble. Those plasters are used on Zegreenlab’s own panels and blocks, and on conventional concrete block homes whose owners simply want the warm, natural appearance.
Curing on lime time
Anyone used to concrete has to reset expectations. Concrete blocks reach an initial hardness in about seven days. Lime products need roughly 28 days, and in Costa Rica’s humid climate, five or six weeks to harden enough to be used. In a dry place like Colorado, the surface might feel dry after a week while the wall is still curing inside. Ashley is clear with clients that the full curing window matters.
She has also observed something the lab data hints at. Repeated wet and dry cycles seem to make the material harder over time. Moisture on its own is not the enemy. Constant saturation with no chance to dry is.
How not to build with it
The most common mistake Ashley sees comes from a specific tropical modern look. Walls that extend past the roofline with no overhang leave the material exposed to constant heavy rain, and bagacrete, like hempcrete, can become waterlogged if it cannot dry between soakings. Good roof overhangs solve most of that.
The other essential detail is at the base of the wall. It must sit slightly above the ground, with a moisture barrier between it and the foundation. The separation can be as simple as five centimeters, a wood beam, a concrete plinth, or a steel element. What matters is that the wall never sits in standing water.
“I often compare it to adobe when I am talking with older Costa Ricans,” Ashley said. It is natural, durable, and long lasting, and it demands the same respect adobe does.
The finished lime plaster is water resistant and works on interior and exterior walls. In bathrooms, Zegreenlab recommends tile on the surface that takes direct shower water, with lime plaster elsewhere in the room, where it helps regulate humidity. Moroccan tadelakt, a lime plaster technique polished and sealed with soap, is another option in wet areas, though it is not currently a Zegreenlab specialty.
Why clients keep coming back
Zegreenlab’s customers arrive with different motivations. Some care most about the carbon footprint. Some want a more comfortable house. Some are drawn to the warm, textured look of natural lime plaster. The material is insulating, fire resistant, antimicrobial, breathable, and helps regulate humidity. In Costa Rica, that translates directly into cooler, drier homes without heavy mechanical cooling. In colder climates, the wall assembly would need to be thicker and more airtight, but the underlying insulation logic is the same.
One hotel project pursuing the Living Building Challenge helped push Zegreenlab through a Declare label for its plasters and blocks, which supports green building certifications that require material transparency and nontoxic content. The clearest signal that the system is working, though, is repeat customers. People take the risk once, live in the finished house, and come back when they are ready to build again.
What a bagacrete wall actually costs
Because Zegreenlab is not highly industrialized, and because most inputs in Costa Rica are expensive, the material is more costly than mainstream construction. Ashley pushes back on the framing though. When clients price out a finished wall, the gap narrows quickly.
A conventional wall usually needs studs, insulation, drywall, texture, and paint. A Zegreenlab wall still uses framing, but the panel is already the insulation, and the wall is finished with a coarse plaster and a fine plaster. The step count is lower. Rolled into the total budget of a house, she said, the difference is not significant, and the buyer picks up fire resistance, breathability, humidity regulation, and a distinctive natural finish along the way.
Beyond walls
Zegreenlab already produces ceiling panels that add warmth and acoustic performance, and the company gets steady requests for them.
Floor tiles made with rice husks and cement have been prototyped, and production molds are the next step.
A dedicated workshop for household products and furniture is in the works so that lamps, tables, and other objects can come out of a proper woodworking space rather than the main production floor.
Ashley is trained as a product designer, and it shows in how she talks about the material. “I see this as an exciting design challenge,” she said. “It offers many possibilities beyond construction.”
Zegreenlab’s own guesthouse, built on the family property after their main home, is now a working demonstration of climate-appropriate design in Costa Rica.
Many foreigners arrive and build in the American style they already know, which can produce houses that are simply too hot. The guesthouse is a return to the older approach.
The wall material is only part of the picture. Airflow, roof overhangs, orientation, shade trees, and the direction of the afternoon sun all shape whether a tropical house is comfortable. Ashley is encouraged by a new generation of Costa Rican architects who are returning to those principles.
The other side of the business
Zegreenlab Construction sits alongside two other family ventures, both led primarily by Ashley’s husband and daughter. Osmosis, their CBD brand, is made locally and sold in Costa Rican pharmacies, where every product must be approved by the Ministerio de Salud and match its label exactly. Ashley acknowledges the challenge of competing on price with imported brands that may not clear the same bar, but their small customer base is loyal. The Void, their hemp jeans line, is run by their daughter and uses a hemp fabric Ashley describes as lightweight and comfortable.
The family also runs an archive worth noting. In the early years, they translated hemp and cannabis research into Spanish and published it, along with interviews, on a channel called MCN, or Medical Cannabis News. Much of that early material is still available.
A brand built on getting it right
Zegreenlab has moved past the friends and personal contacts phase. Architects specify the material by name, projects are booked out for months, and the company has enough completed homes on the ground to point to real world performance rather than laboratory promises.
“We have managed to build a brand and a dependable reputation,” Ashley said. In an industry where hemp and lime construction is still often treated as experimental, that may be the most important product Zegreenlab has made so far.
Learn more about Zegreenlab and its brands at zegreenlab.com. Contact Ashley Javogue at ashley@zegreenlab.com.
