Renco Blocks

Building with Life-Size LEGOs: How Renco’s Renewable Composites Are Transforming Construction

Life-size LEGOs offer the potential for building that’s faster, cheaper, stronger and greener

Probably everyone in the building industry has looked at LEGO® blocks and wondered why no one makes life-sized versions.

Engin Yesil, a serial investor from Turkey, was watching his son play when he decided to make it happen, creating blocks of renewable composite (Renco for short) made of recycled glass fibers, recycled plastic, resin and stone. He quickly gained approval to build with the new material in his native country. In the United States, however, he faced a massive obstacle—the International Building Code (IBC) didn’t approve construction with anything but concrete, wood and steel.

To get IBC certification for use of the Renco system, Yesil partnered with Thomas P. Murphy Jr. and Kenneth Smuts, co-president and former vice president, respectively, of Miami firm Coastal Construction. Smuts, a licensed professional engineer and now president of Renco, spearheaded the research and development of the Renco Structural Building System and, over a decade, codified and secured approvals under the IBC.

Exhaustive evaluation backs up the Renco building system

Although Renco attests that its blocks are 23 times stronger than concrete, the fiber-reinforced mineral composite weighs only 20% as much. Injection molding means the material can be formed in whatever shape is needed—blocks, roof beams, joists or flooring—that can all withstand 275 mph winds and are rated for a Category 5 hurricane. The composite is completely water-, mold- and even termite-resistant, as well as ANSI-certified for structural performance. Tweaking the composite achieves the required fire ratings. That’s not as much of an issue for single-family residences where homes are 10 feet apart, but for multi-family, blocks must pass rigorous one- and two-hour fire tests.

A critical decision was how to hold the blocks together. After opting for adhesives rather than metal fasteners, the team investigated possibilities and settled on methyl methacrylate, a bonding agent used in marine, aerospace and trucking products. The adhesive works well with wood, steel and composites.

To compare the carbon footprint of the Renco structural system with others, Renco worked with Vancouver-based consultant BAS Carbon to produce the environmental product declarations for linear components, joists and decking. The results show a smaller carbon footprint compared with reinforced concrete and structural steel buildings. Assembling the building doesn’t require heavy cranes, power tools or big machines, so construction is also more energy efficient.

Sizes, shapes and colors make designing easy

In Turkey, the Renco block is a nominal 4”, which meets many US requirements. For example, Smuts grew up in New England, where most wall thicknesses are 4” to 6” depending on whether framing uses 2” x 4” or 2” x 6” material. But in Miami, construction is predominantly 8” masonry to achieve the strength needed in high-velocity hurricane zones. As a result, Renco manufactures two sizes of blocks—8” commercial and 6” residential. Consistency helps with construction planning, setting the stage for efficient execution. “We wrote a prescriptive evaluation report,” Smuts said. “We determined the design loading and the compressive, tensile and flexural capacities of the blocks and floor decking. We also developed joist tables and span tables for the joists and decking. We have a cookbook for our process that’s easy to translate and share with others and adapt as well.” When designing a structure, architects can simply grab different shapes and sizes in CAD, then copy, cut and paste them to represent the building’s components.

Color coding also makes it simple for a nontraditional workforce to quickly assemble a building, a plus in an industry plagued by labor shortages. Workers can look up the colorized scheme on a tablet or roll out a set of plans and see that a gray block is 8” x 8” x 16” or a blue block is 8” x 8” by 48”. “Labor picks up the color control system in an hour or two and knows exactly how the blocks fit together when they proceed with building,” Smuts said.

Given that Renco manufactures only the pieces needed for a structure, the construction process supports a cleaner environment, with no need for garbage bins or cutting and minimal waste. Although every type of material is expensive, the ease of construction and lack of waste with Renco blocks can save developers 5% to 10% on project costs.

“Developers focus on what brings them the highest return for their efforts,” Smuts said. “It’s the same amount of work whether they’re building a couple-hundred-unit apartment complex or a 500-unit high-rise condominium. Workforce housing often gets ignored, but building with Renco can still mean a nice ROI.”

Timing is everything

After years of comprehensive testing, Renco secured approval from IBC in 2019—right before the COVID-19 pandemic hit. Supply chain and port issues quickly escalated, and the cost of shipping just one pallet of Renco blocks to the United States rose from $3,200 to $15,000, according to Smuts. The price jump wiped out much of the economic advantage of building with Renco blocks, making it clear that US construction could no longer use material imported from Turkey.

That explains why Renco has completed only one project, the 96-unit Lakewood Village apartments in West Palm Beach, Florida. The recently completed complex was built in eight weeks by 11 unskilled workers using mallets and glue guns. But Renco also began building a 60,000-square-foot manufacturing facility in Jupiter, Florida, that will come online soon.

“We’ve started to build a book of business commensurate with that opening,” Smuts said. “So now the product will be built in America with American labor in an American facility.” Renco is targeting housing starts in Florida, Texas and Arizona to accelerate the sale and implementation of Renco products.

The system has also earned worldwide recognition, including first place in the 2024 JEC Composites Innovation Awards, the Best Construction Product Design of 2023 at the BLT Built Design Awards and the Gold Award at the International A’Design Award & Competition. Seems everyone recognizes the value—and appreciates the innovation—of using LEGO-like bricks for construction in the real world.

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