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.

The way we construct buildings in the United States hasn’t changed much in decades. But with the confluence of high materials prices, a skilled labor shortage, high mortgage rates and sustainability challenges, the construction industry has a need for change.

In short, there’s “an importance of trying to figure out new ways of doing things,” said Joe Benvenuto, chief operating officer for contractor LIFTbuild. The Southfield, Michigan-based company is finding success with an unconventional construction process: building from the top down, with a patented method that LIFTbuild refers to as “vertical manufacturing.”

Elevated idea

To be sure, top-down construction—where the top floor is built first and the process works its way down—isn’t totally new. Architect David Termohlen is credited with having invented the concept and further developing it in the 1970s with Charles H. Thornton, founder of Thornton Tomasetti structural engineering firm. A few buildings such as the Russian Diplomatic Compound in Riverdale, New York City, were built in the early 1970s. But then the idea—and the patent—languished, with some exceptions. 

In 2017, Detroit-based Barton Malow, a now-100-year-old construction company, made an investment in the top-down approach to construction, “which fueled the effort to innovate the concept of building a building starting at the top and working downward,” Benvenuto said.

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The company established LIFTbuild to meet its goal of doubling construction efficiency, and it spent about three years in research and development to improve the concept, the way the building is designed and constructed, the way the floor plates are connected and the way they’re lifted.

“In some cases, we sent the engineering methods through destructive testing to validate the process. What LIFTbuild is trying to do elevates the process to create a safer and less expensive way to build commercial buildings,” Benvenuto said. “These R&D efforts have resulted in more than 15 US patents, which protect LIFTbuild’s unique technological and delivery means and methods.”

Benvenuto added, “by 2020, LIFTbuild had significantly improved system safety with innovative means, methods and technologies centered on the superstructure, façade, assembly pad and lifting. Improved safety, increased efficiency and higher quality all lead to a better and more sustainable product for our end user.” 

The Exchange

Built on a small, tight, triangular site surrounded by streets, businesses and the elevated light rail system known as People Mover, the 16-story high-rise called the Exchange in Detroit is LIFTbuild’s first proof of concept. It comprises 153 residential rental units, 12 condominiums, ground-level office space and approximately 6,000 square feet of commercial space. 

The structural steel and concrete building took extensive planning, with much of the engineering done in a 3D model and a virtual environment. LIFTbuild then created a kind of manufacturing environment on the site. “Picture more of an assembly line in which a vehicle gets created. It’s very rapid. All the critical parts and pieces come into the process at just the right time,” Benvenuto said. 

The build works this way:  

Builders start on site by completing the foundation and underground work consistent with a conventional building. They then begin erecting concrete and steel “spines.” The spines are structural elements and could include stairwells, bathrooms, kitchens—anything, really, depending on the design, according to Benvenuto.

Next, they begin placing the concrete assembly pad, what LIFTbuild refers to as the factory floor. The assembly pad is located exactly where the building footprint is. A building’s design and geometry determine the number of spines needed. The Exchange has two, each of which encase elevators, stairs, storage and mechanical rooms.

Strand jacks, linear winches that pull heavy loads from above, are staged at the top of the spines. The floor plates are then built around the spines, about three feet off the ground with metal decking and concrete. The jacks lift the floor plates just above the builders’ heads to install the underdeck mechanicals—no need for scaffolding or ladders.

The façade and rough mechanical, electrical and plumbing go in before the floor plate is lifted. After the floor is locked into place, interior fit out begins, which includes interior walls and ceilings. Once the façade and fire protection are installed, the floor plate is lifted by the strand jack into place. Each floor in the Exchange weighs about 1 million pounds, and during placement rose about 30 feet an hour. The highest lift on the Exchange was about 200 feet.

“Placement is a cantilevered approach where we structurally connect that floor plate to the spine,” Benvenuto said. “From there the floor plate is able to provide structural stability out all the way to the exterior of the building without columns.” Every floor plate is individually supported. 

Lift and learn

The foremost reason to use this method is safety, Benvenuto said. According to the Bureau of Labor Statistics, in 2022 the construction industry accounted for 1,092 deaths by falling, slipping or tripping—47.4% of all workplace fatal falls, slips and trips. “We eliminate the hazards when we install the façade at ground level. Fall protection is naturally built into it,” Benvenuto said.

Benvenuto cites increased productivity as the next major benefit, pointing to the difficulty of finding available, qualified tradespeople, rising construction costs and material pricing. “Projects have a hard time meeting financial feasibility at times,” he said. With LIFTbuild, because assemblies are done on site, often using prefabricated products and with little need for large cranes, there are fewer people needed for a build. 

The method also saves time. Although builders could customize individual floors, each floor is basically a repeat of the one above. There’s more of a manufacturing process—which also can instill better quality, said Mark Tamaro, managing director of Thornton Tomasetti, who consulted on the Exchange.  

Tamaro also points out that these projects can be more sustainable. Because the floor system uses steel frames, it requires less material than concrete construction. “There’s a significantly lower amount of embodied carbon than in a typical concrete product,” he said. Additionally, Tamaro said that as they learn more, there may be ways to incorporate mass timber or other materials. 

Ultimately, LIFTbuild can be less expensive when compared to conventional building. Benvenuto said that using LIFTbuild, the company aims to provide savings of 10% to 20% on cost and 20% to 30% in schedule savings. 

Nothing is without its challenges, however. There’s a certain level of education—for municipalities, lenders, insurance companies, builders and tradespeople—that must happen. Benvenuto said the company went through some “pretty intensive education sessions to make sure they truly understand what’s happening and address any concerns or what they would perceive as a risk.”

Tradespeople and others working onsite had safety training and “education around optimizing their time on site to make sure they were the most productive,” Benvenuto said. “But realistically, the work conditions are better and easier than you would see on a conventional project,” he added.  

The education piece helped with permit applications and inspections. “Some of the preliminary inspections can happen at grade level, so it’s advantageous for them,” Benvenuto said. 

LIFTbuild also collaborated closely with MIOSHA to adhere to all safety standards. The strand jack system is safe, able to take four to five times the amount of capacity needed to lift the floor plates. 

Not just a novelty

Top-down construction can work beyond commercial building. There’s need for more housing, and the LIFTbuild method is “well-suited for residential construction,” Tamaro said. The method could be a game changer for the industry.

“This is something that can truly transform the way we build buildings,” Benvenuto said. “About 10 years ago, Barton Malow set the goal of doubling our efficiency by our 100^th anniversary [in 2024]. The investment into LIFTbuild is a significant effort to accomplish that.” 

While the Exchange is LIFTbuild’s first completed building, Benvenuto said they have a handful of opportunities coming. “With the Exchange, we’ve been able to validate the technology. Now our focus is to commercialize LIFTbuild on a broader scale throughout North America.” 

Top-down in action: A different take

In 2014, Thornton Tomasetti used the “traditional” top-down build method to build the Marriott Marquis in Washington, D.C., said Tamaro, who was the project’s engineer of record. “We constructed the building both upward from the ground level and downward simultaneously.” 

Builders drill into the site and install shafts, called piers or plunge columns, Tamaro said. In the case of the Marriott these were dug down about 130 feet to get below the lowest basement level. The piers stop at the floor level of the first floor. The build continues upward in the traditional way with concrete columns. 

At the same time workers are building up, others are excavating below, around the piers. “If you do it right, you can top out the building before you get to the bottom of the basement,” Tamaro said.

Why do it this way? “In the case of the Marriott job, there were two fundamental reasons,” Tamaro said. “One is speed of construction.” In a conventional build you’d dig all the way to the bottom and then come back out. With this top-down method, you effectively start in the middle and work down and up at the same time. There’s no wait time. 

The other reason to choose this method is that this particular site was constrained with both a high water table and the need to go extremely deep as there were multiple basement levels. “This method of construction allowed us to build deeper and avoid having to address the groundwater,” Tamaro said. “Doing things this way made an otherwise very challenging project feasible.”

Concern over the environment is driving change in the built environment. From the focus on reducing waste in construction to the 2030 challenge of developing carbon-neutral buildings, the construction industry is determined to go green. LEED certification and passive house are two green construction standards that have existed for some time. Passive house is less widely known but growing in popularity.

LEED vs. Passive House

Leadership in Energy and Environmental Design (LEED) was developed in the early 1990s and has been updated several times. The green building certification program is overseen by the U.S. Green Building Council (USGBC) but is recognized worldwide.  There are four different certification levels.

“LEED certification provides a framework for healthy, highly efficient and cost-saving green buildings, which offer environmental, social and governance benefits,” according to the USGBC website.

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Unlike the comprehensive approach of LEED, passive house is narrowly focused on energy efficiency and developing a building that uses no more energy than it produces onsite. There are five principles of passive building. They are based on insulation, building envelope, ventilation, space conditioning systems and windows. 

While passive house is older (the term was coined in 1982, but the principles were applied in the 1970s) than LEED, it is less common. Although developed in the United States, it blossomed in Germany, but there’s rising demand for passive houses stateside.

Not Only a Passive House

Despite the name passive house, the concepts apply to any building type. 

“Because cost-optimization strategies for high-performance buildings are less well known earlier on, and there could be more upfront costs, long-term owners have typically been the most interested in developing high-performing buildings,” said Rob Hosken, an architect who grew up in a passive solar house in the 1980s and is a principal at Building Performance Architecture, which performs design reviews and quality control inspections and testing of buildings. 

However, passive house techniques are more commonly used on single-family homes, multifamily dwellings and university buildings.

Passive house techniques can be followed in any environment, but more extreme climate conditions are particularly appropriate since owners would save more on energy. “Passive house is a smart design to consider when the local climate of a building is a factor,” said Joseph Wheeler, an architect and professor at Virginia State University.

One of the major draws of passive house building is the savings in energy bills. According to the Center for Energy and Environment, “Passive house-certified buildings are up to 80% more efficient than a home built to typical energy code.”

Bill Spohn and his wife live in a passive-leaning home (not certified) in Pittsburgh. Their electric bill has been $0 for the past year. Spohn, a trained engineer, is the CEO and founder of TrueTech Tools, which sells tools that determine building performance. He’s a passive house enthusiast.

Spohn adds passive house construction leads to a more comfortable living environment. “There are no cold or hot rooms or drafts; instead, each room is comfortable and at the same temperature.”

Limitations to Growth

Between the cost savings and environmental benefits, a passive house seems like a great option for new buildings. So why aren’t more structures developed based on passive house principles?

“I appreciate generous natural light in a space, which may be limited in a passive house due to the strict insulation requirements and higher cost glazing,” Wheeler said. “The passive house standard is an extreme standard and works well in harsher climates; however, it’s better to balance all aspects of design, construction, energy efficiency and cost when building in more moderate climates.”

There are also higher upfront costs—about 3-5% for a conventional home and 0-3% for a multifamily home, according to Phius, a nonprofit that certifies passive house projects in North America. “In general, the larger the building, the smaller the cost difference,” Phius adds.

Spohn predicts there will be zero extra cost to build a passive house. “Architects and builders are developing good practices and design principles that are driving the cost of passive house down.”

Wheeler notes that the extra upfront costs compromise how much house people can afford.

Skills Gap

In theory, passive house construction doesn’t take longer than standard construction. Yet, this isn’t the case in the real world.

“If the architect and general contractor have no experience with passive house, it will be a challenge because it’s a different way to build, requiring more attention to the high-performance construction details,” Hosken said. “Once an architect and contractor have a few passive house projects under their belt and learn how to navigate the technical and budget challenges, the cost and time of construction will go down.”

Spohn concurs: “If the tradespeople know how to work with a passive house, it should not take more time to construct.” However, because it is niche at this point, many tradespeople are unfamiliar with the principles and may pass on passive house projects.

Increasing Demand

Passive house buildings are environmentally friendly and comfortable to live in. So, what can be done to encourage more of it?

Both Spohn and Hosken believe it comes down to awareness. “The industry needs a public champion to encourage others to learn more,” Hosken said. “Widely used public buildings would also be helpful so people could experience them and recognize their comfort.”

Another way to move the needle forward is for cities and municipalities to enshrine passive house principles into building codes. A handful of municipalities are beginning to adapt their building codes and encourage passive house techniques.

Many are striving to reduce the strain construction puts on the environment. The two green construction standards—LEED certification and passive house—greatly reduce the carbon footprint. Building via the lesser-known passive house techniques results in buildings with greatly improved energy efficiency.

Maybe you’ve been there—the music is bumping; the vibe is right. Many people could spend all night on the dance floor in a happening night club, especially when they’re young—if only most dance clubs weren’t so hot. Those sweaty, packed clubs might not be the most comfortable places to be, but as Glasgow-based venue SWG3 has discovered, such heat-generating hot boxes can be a potent source of clean geothermal energy.

Built spoke to David Townsend, director and founder of the award-winning geothermal energy consultancy TownRock Energy, about how one dance club has become an unlikely power source.

An unusual power source

Townsend has nurtured a lifelong fascination with geothermal energy. “My whole career, since founding TownRock Energy in 2013 right out of university where I studied geology, has been focused on exploring and applying all of the ways that heating and cooling can be provided from technologies installed in the ground,” he said.

Because of his passion for all things geothermal, it’s no surprise that the concept for SWG3’s innovative body-heat-powered dance floor came to him long before he consulted with Andrew Fleming-Brown, SWG3’s owner, about transforming the arts and events venue into the world’s first geothermally powered night club.

“The inspiration started when I was overheating at the front of a music gig in a poorly ventilated club and realized how much heat is given off by the crowd,” Townsend said. “But the idea didn’t fully materialize until my first meeting with Andrew.”

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Once the two put their heads together, they realized that all that power Fleming-Brown’s dancers and event attendees were generating could be put to good use.

“This type of geothermal energy technology has many advantages,” Townsend said. “It’s very high efficiency. Typically, one unit of electricity in gives four to five units of heat out, which increases when the boreholes have been previously heated up during a cooling cycle. It also has minimal surface impact, since all of the new plant is contained within a repurposed shipping container, and the rest of the infrastructure is all buried underground and silent.”

On top of that, Townsend’s storage solutions mean that all the energy the system is generating will be put to good use. “Nothing is wasted,” he said. “Using geothermal storage allows for heat to be stored over days, weeks, months and even years, as opposed to hot water tanks, which store for a mere couple of days, or air-conditioning, which does not store any heat.”

Making the dance-floor-powered club a reality

While the concept of a dance-floor-powered space might have been intuitive, Townsend said it took creativity and thinking outside the box to turn the idea into reality.

“Every dance floor that has hundreds or more people and good music generates heat, but capturing this heat and storing it for use another day is an innovative process,” Townsend said.

First, the system must efficiently remove heat and moisture from the occupied space, so the process can begin. “Air-conditioning units in the ceiling, which remove heat and moisture from the air, transferring the heat into refrigerant, which runs through pipes to the heat pumps,” Townsend said.

From there, the heat travels throughout the club. “The heat pumps transfer the heat to a 2.5 km loop of vertical borehole pipes via a water-based circulating fluid,” Townsend said. “This cycle can be reversed to bring heat back out of the ground and into the dance floor (literally, as it also connects to underfloor heating).”

At the end of its journey, the heat is efficiently stored until it is needed to provide energy. “Heat is stored underground in the rocks beneath the community garden,” Townsend said.

After designing the system, construction began. “The construction program, including tendering to secure contractors and permitting, ran from July 2021 through to August 2022,” Townsend said. “COVID and the associated meltdown in the global supply chain caused a few headaches and delays.”

Once those delays were resolved, “90% of the construction itself was carried out from January to June 2022,” he said, before the club was ready to open. “The system has been operating since September 2022,” Townsend said, later adding that, “patrons have been excited to hear about the technology, and the story has been incredibly well received on social and mainstream media.”

A greener, groovier future

“This is the first time that geothermal boreholes have been used to store body heat from dancers in a club,” Townsend said. But he hopes that it won’t be the last.

“All venues should be using this technology in some form, so as to eliminate fossil fuel use for heating and hot water,” he said. “The biggest barrier we are facing is that most venues do not own their building and the landlords are challenging to engage.”

With an increasing number of governmental organizations valuing green energy and building technologies, future incentives like subsidies and tax credits could help persuade venue owners to adopt similar solutions, or at least take a second look at areas where their spaces could easily go green.

Ultimately, Townsend said he hopes SWG3 will inspire construction professionals outside the nightlife world to take a closer look at the natural sources of clean, geothermal energy that surround us. “We hope this inspires everyone to think about how waste can be repurposed to have value,” Townsend said. “In cities waste heat is everywhere, and if we captured, stored it in the ground and reused it we would be able to eliminate the 30% of our carbon emissions that come from heating and cooling buildings.”