CIRCL in De Morgen: Fast, ecological, and affordable building.

Building a new home is stressful for people and the climate. That is why CIRCL builds circular homes that emit less CO2, are built quickly and smoothly, and cost no more than a traditional house. "We want to tear down the entrenched mindset in the construction sector." "We call it our digital architect. Just take a look," says Wim Pieters (28). We are sitting in the living room of the brand new villa belonging to Stef* and Sandrine*. Outside it is thirty degrees, but inside it remains cool, even though the large windows look out onto the garden and the woods.

On his laptop, Pieters, the very young CEO of CIRCL, demonstrates how you can enter the location of your plot and your preferences into an online design module. Within fifteen minutes, you receive a building plan proposal and a detailed quote, including the complete cost breakdown.

"For homebuilders, it is often unclear what is spatially possible and what everything will cost. That is the reason for this software," Pieters says. "Everything is included, down to the very last power outlet. We then further develop the base plan. The price will not change anymore." In the construction world, that is exceptional: no unexpected additional costs. But Stef, who has lived in this sleek villa since May 10th, can confirm it.

"We actually did not want to build a new house because it puts such a strain on the environment. Still, we wanted to move," he says. "When my wife and I saw this beautiful piece of land, we could not resist, and we began looking for ways to build ecologically."

No rough wool socks feeling

That sounds like quite a challenge. "The way we live and build accounts for 36 percent of our carbon footprint, 40 percent of our energy consumption, and 33 percent of our water usage," says Jan Verheyen, spokesperson for the Flemish waste agency OVAM. "And one third of all waste and material streams generated in Europe comes from construction."

CIRCL is one of the companies looking to change that. The start up from Geel has been around for two years and has already sold seventy homes, ten of which are completed and the other sixty under construction. At the moment, these are mainly newly built homes in the higher price segment.

"With our completed and ongoing projects combined, we achieve a CO2 reduction of 3,324 tons," says Pieters. "And these are not homes that give off a rough wool socks, alternative lifestyle feeling."

In the spacious home of Sandrine and Stef, there is indeed no visible sign that it produces at least 55 percent less CO2 emissions than the newer villas down the street. That is precisely the point.

"Some clients have a skewed perception of a sustainable home," says Pieters. "'Will it start rotting after a while?', 'Will it really stay standing?', they ask, for example. But just because we maximize biobased and recycled materials, build modularly, and combine energy efficient technologies such as heat pumps and solar panels with thorough insulation, does not mean our homes are flimsy forest shacks."

Housing shortage

Michiel Ritzen, sustainability expert at VITO/Energyville, praises CIRCL's approach. "Building with prefabricated modules and biobased materials is sustainable, you save materials, require fewer workers, and the greater precision leads to fewer unexpected costs," he says. "This offers an answer to the housing shortage, the major environmental impact of construction, and high prices."

However, that is not yet common knowledge among the general public. Stef: "Our architect was skeptical at first. But that quickly turned around because CIRCL had answers to every difficult question and collaborates with reputable, reliable suppliers. It is a wonderful, normal house. What strikes me now that it is so hot, is how cool it stays, even with the large windows that have been open," says Stef.

Pieters knows why that is. "Our homes rest on thin concrete slabs with insulation situated on the underside," he explains. "Combined with floor cooling, that functions like a cold battery. The insulation materials and roof finishes are also designed to keep out as much heat as possible." The home of Stef and his wife not only feels comfortable, it also looks like a house you could find in a design magazine. Paired with that green comfort, you might easily assume it costs a fortune. Yet this house is not more expensive than a traditional build of the same type. "We had an average budget for a home like this, and working with CIRCL did not cost us more," says Sandrine.

The price for a turnkey, fully finished CIRCL home ranges between 1,600 and 2,600 euros per square meter (excluding VAT), which is competitive. "And the fact that we build quickly can offer a financial benefit," says Pieters. CIRCL assembles its houses within twelve weeks. That means renting for less time or paying bridging loan interest for a shorter period. Construction on Sandrine and Stef's home began on February 3rd, and on May 10th, the family moved in. "For us, it was a joyride," says Stef.

Puzzle

CIRCL can build fast, green, and at an average price point thanks to industrialization, automation, and digitalization of the building process, along with the use of ecological materials, techniques, and principles.

The homes are composed of a puzzle of elements and modules manufactured in partner production facilities, guaranteeing exceptional precision and time savings. Around seventy percent of every home is prefabricated. The modules contain, among other elements, the skeleton, which consists mainly of timber framing, the staircase, and a standardized utility box that houses the heat pump, ventilation system, and the solar panel inverter.

Still, CIRCL homes look distinct every time and do not bring to mind ugly, dull prefab structures, because the walls can be varied. Pieters: "Compare it to chassis in the automotive industry. They are also shared across different car brands. There are certain constraints, such as the bathroom model or the stairs. But even then, we do our best to match the client's taste." For instance, the staircase in this house is L shaped rather than the standard U shape. The utility box sits halfway above the stairs as standard practice, saving valuable floor space.

Also practical, sustainable, and time efficient: pipes, wires, and other technical elements run inside the ceiling rather than being cast into concrete or hidden inside solid walls.

"In a traditional house, you build walls, chase grooves into them to run cables, and then patch those walls up again. That makes no sense," Pieters says. "By using compact technical modules that are not cast in concrete, we consume fewer materials, and thanks to slimmer walls, we gain seven percent in usable floor area compared to a traditional house. That amounts to an extra room."

Old newsprint

The climate benefits stem from energy efficient systems like the heat pump and sustainable materials. Seventy percent of these are biobased and forty percent are recycled. A prime example is the insulation inside walls, floors, and the roof: it consists of cellulose made from old newsprint. That is far more climate friendly than standard plastic rigid foam, which contains compounds up to 3,200 times more damaging to the climate than CO2.

Furthermore, the roof membrane is installed without glue, and white gravel covers the flat roof, protecting it from heat and UV radiation. Beneath the roof covering lie boards made of recycled expanded polystyrene that are not glued down and can be completely recycled.

Sandrine and Stef did choose a travertine kitchen countertop and laminate cabinetry. "We are environmentally conscious, but a sustainable countertop made from beetle shells turned out to be five times more expensive," Stef says. "We are not that extreme."

Pieters also embraces green realism. "We want to convince as many traditional home lovers as possible," he says. "You cannot do that by forcing strict choices. Our houses are technically as green as can be, but when it comes to interior decor, you can do whatever you like, even if it is not the most sustainable choice."

Either way, the vast majority of clients do not turn to CIRCL out of pure ecological conviction. Stef and Sandrine were exceptions. For instance, they suggested using carbon negative facade bricks themselves, reducing the home's carbon footprint even further. "Most people are not preoccupied with sustainability," says Pieters. "It is mainly the fixed pricing and total transparency that attract them. In that area as well, we want to challenge the traditional construction industry."

Energy efficiency

The scale up, which employs eight people, works with dedicated partners such as Deceuninck, Vandersanden, and NIKO for windows, bricks, and home automation, all companies possessing deep technical expertise in their domains.

Another advantage: the foundation of the building concept was developed alongside KU Leuven, Buildwise, Embuild, and the sustainable innovation center Kamp C. CIRCL is also a subsidiary of the construction group Groep Vanhout, established in 1928, and part of the BESIX Group, the largest construction group in the country.

Through economies of scale and more efficient methods, CIRCL intends to offer affordable houses and apartments over the longer term.

According to sector organization Embuild, companies of this type have the wind in their sails. "Ever since the 2023 energy crisis, energy efficiency has become a top priority for consumers," says spokesperson Sven Nouten. "And businesses using modular building offer great benefits, such as rapid construction times and the flexibility to adapt the home and reuse materials and components."

The fact that materials are becoming more costly is not an obstacle. "Because we use as little steel, cement, and concrete as possible, the current market dynamic works directly to our advantage," says Pieters. "It also shows how traditional, slow, and wasteful construction methods no longer belong in this day and age. We want to demolish them."

(*) For privacy reasons, the residents remain anonymous. Their full names are known to the editors. Source: Building fast, ecologically, and affordably: 'For us, it is actually an advantage that materials like cement and concrete are becoming more expensive'. (2025, July 14). De Morgen. Retrieved July 14, 2025, from: https://www.demorgen.be/beter-leven/snel-ecologisch-en-betaalbaar-bouwen-voor-ons-is-het-net-een-voordeel-dat-materialen-zoal-cement-en-beton-duurder-worden~b49cac9d/