Drawing from Tradition and Developing Natural Materials: Solutions to the Sustainability Crisis in Construction
Contemporary construction heavily relies on the steel and concrete industries, which are responsible for about 15% of global annual greenhouse gas emissions. The construction sector also consumes half of the world’s annually extracted virgin materials. In Finland, construction accounts for one-third of annual emissions. The sustainability transition in the construction sector is a matter of urgency: the climate crisis cannot be solved without it.
In Finland, one of the pioneers of sustainable architecture is Collaboratorio, founded in 2016 by Kristiina Kuusiluoma and Martino De Rossi. At its core are ecological thinking, healthy and pleasant living environments, and long building life cycles. Collaboratorio is an example of how even a small actor can influence the direction of an entire industry—by drawing on tradition while developing new solutions.
“We saw that the only way to operate sustainably, even radically, was to start our own firm. New construction is always an environmental crime. When a client contacts us, we first assess whether the need is real, whether existing spaces could be used—and if something must be built, how to do it in the most ecological way,” says Kuusiluoma.
Natural Concrete from Clay and StoneIn 2016, there was no natural material on the market comparable to concrete in strength and durability, so Collaboratorio began development work and, the following year, partnered with the concrete firm Vihdin Betoni. The result was a natural concrete made from unfired clay and aggregate, with just 4% of the carbon emissions of regular concrete. In other words, the emissions of one conventional concrete floor equal those of 25 natural concrete floors.
“Natural concrete requires no virgin materials. The clay comes from excavation work, such as foundations or roads—if we can access it before it’s sent to a landfill,” Kuusiluoma explains.
The aggregate used in the material is fully recycled. Collaboratorio and Vihti Betoni even won a Helsinki circular economy competition for repurposing Finlandia Hall’s marble tiles into crushed decorative material for natural concrete floors, benches, tables, and other products. These products are also fully recyclable, and the recycling process is energy-efficient.
“If a natural concrete floor is removed, it’s moistened back into a pliable mass, collected, mixed, and compacted again into a new surface or a new product,” says Kuusiluoma.
The newly founded company Luonnonbetoni Oy, established by Collaboratorio and Vihdin Betoni, is currently developing floor slabs and load-bearing wall structures from the material, with partial funding from the Finnish Ministry of the Environment. According to Kuusiluoma, the material has huge potential, even though its international expansion is only beginning. Responses vary between countries.
“In Finland, the attitude is very cautious. Larger actors want at least five similar references, which makes it hard to get started. In Denmark, on the other hand, everyone wants to be first. We’ve accepted that the material will likely gain traction first in the Nordics and Baltics—and Finland will follow.”
A Love for Structures and Materials
At Collaboratorio, the starting point for building design is a 400-year life cycle. A hundred years ago, almost all houses were solidly built, meaning that a single material was responsible for both load-bearing and thermal insulation. A simple structure without vapor barriers or insulation layers is reliable and long-lasting. As the number of layers and the thickness of insulation increase, the risk of errors and malfunctions increases, which can lead to moisture damage, for example.
Structures and building materials also play a significant role in adapting to the climate crisis. Solid structures, for example, withstand wet winters better than multi-layer structures that are susceptible to moisture damage. Hot spells are becoming more common, even here in the north, which increases the adverse effects of heat.
“We have a test apartment in Italy with clay plaster. During a 42°C heatwave, the indoor humidity was about 50%, compared to 80% in a conventional apartment. The experience of heat is entirely different—humidity makes it feel suffocating,” Kuusiluoma explains.
As buildings increasingly rely on renewable energy sources like geothermal heating, construction materials account for a growing share of lifecycle emissions. NNatural materials are not only climate-friendly but also people-friendly: their use has been proven to increase well-being and living comfort. Wood balances temperature fluctuations, is acoustically pleasant, and improves indoor air quality. Clay, on the other hand, binds moisture, purifies harmful substances such as ozone from indoor air, and is a naturally fire-safe material.
“We want to use durable, pure, time-tested natural materials like wood, straw, and clay. The construction industry suffers from the same throwaway culture as the fashion industry. Society simply doesn’t love materials enough,” says Kuusiluoma.
In addition to low carbon emissions, several other factors define a material’s sustainability. Working conditions must be fair, local production is preferable to long-distance transport, and manufacturing should not accelerate biodiversity loss. It’s also important to consider whether materials contain or involve harmful chemicals. Many standard construction products contain flame retardants, some of which are linked to neurological disorders.
“Unfortunately, construction materials don’t come with an INCI list. Product information is still considered a trade secret. For us, material ethics means it must be good for both people and nature. The entire production chain has to be sustainable,” Kuusiluoma emphasizes.
Policy Must Catch Up
While the contributions of responsible actors are essential, they are not enough. A sufficiently rapid sustainability shift in the construction sector requires stricter regulations. Finland’s Ministry of the Environment is preparing national CO₂ emission limits for new construction, to be phased in starting in 2026. However, Denmark’s thresholds are far more ambitious and cover a wider range of building types, including vacation homes and unheated parking garages. Finland’s proposed limit for residential buildings is 16 kgCO₂e/m²/year—while Denmark’s is 7.5 kgCO₂e/m²/year.
“- The regulation is usually also the maximum, as few clients set the bar higher. Everyone is waiting to see what happens, but change is underway. Collaboratorio is still a niche player, but people are no longer laughing at our clay models. It is gratifying that large clients, such as cities, have begun to demand more sustainable construction,” Kuusiluoma says.
The illustrative image accompanying the article shows Collaboratorio’s massive wooden apartment block Kuokkalan Kalo, completed in Jyväskylä in late 2024.
Author: Saana Katila