Architect Matti Kuittinen presents the House Shadow tiny home concept
Architect Matti Kuittinen presents the House Shadow tiny home concept

Recycled steel and circular economy: House Shadow shows the way

A new house has sprung up in the Finnish town of Lohja that might revolutionize the way we think about building and living. Architect Matti Kuittinen, Professor of Sustainable Construction at Aalto University has designed a tiny house where eco-friendliness and resource efficiency converge. A masterpiece of sustainable architecture, House Shadow is the result of collaboration between Aulis Lundell, Vesivek and SSAB using SSAB Zero™, a virtually fossil carbon emission-free steel, in the load-bearing steel structures and part of the façade.

Circular economy showcase

House Shadow has been built from recycled and re-used materials and is part of the Tiny Homes research project. Kuittinen hopes that his research will show how single-family housing can be made as low-emission and resource-efficient as possible. House Shadow is a tiny house that represents minimalism on three fronts: use of natural resources, lifestyle and architecture. 

Architect Matti Kuittinen presents the House Shadow tiny home concept in a video.

This is the first time that virtually zero fossil carbon emission-free steel has been used in load-bearing structures and part of the façade

Matti Kuittinen, Architect and Professor of Sustainable Construction at Aalto University

Load-bearing structures by Aulis Lundell Oy
Modular solutions and load-bearing structures with lightweight Lundell-Profile building materials by Aulis Lundell Oy.
GreenCoat® made from SSAB Zero™ in facades by Vesivek
GreenCoat® made from SSAB Zero™ in facades by Vesivek.

Best building materials have already been made

Kuittinen has long thought about how to minimize the environmental impacts of construction. He thinks that the best building material is that which has already been made.

“The raw materials used to build the planet are dwindling. At the same time, we need to reduce emissions from the built environment by 80–90% and to build nearly 2 billion new homes before the end of the century. These needs are not compatible, which is why radically different housing and construction solutions should be considered,” Kuittinen points out.

According to Kuittinen, minimalism means carefully considered use of materials and the least possible consumption. This approach is reflected in each detail in the House Shadow, which has been designed to use minimum space, energy and materials. It is both mobile and modifiable, and its minimalist structure challenges traditional ways of building and especially of living. 


Virtually emission-free, scrap-based steel

SSAB Zero™ had a key role in the sustainable solutions in House Shadow. This innovative steel has been made completely from recycled raw materials with virtually zero fossil carbon dioxide emissions. The SSAB Zero™ steelmaking process has been designed to significantly reduce carbon dioxide emissions and the company is committed to full transparency in all matters related to carbon dioxide emissions. 

The carbon footprint of the steel supplied by SSAB has been verified by a third party. Since steel is the largest contributor to customers' carbon footprint, full transparency in steel CO2 emissions is essential.

“This is the first time that virtually fossil carbon emission-free steel has been used in load-bearing structures and part of the façade. This new way of making steel will be significant in reducing emissions. Steel is a good material otherwise for a building designed to be moved and completely prefabricated, as it provides both lightness and durability,” Kuittinen notes.


Circular economy benefits

Using the circular economy in the construction sector significantly reduces the environmental impact of construction projects. House Shadow shows that recycled and reused materials can be used flexibly and innovatively. This creates new opportunities for more sustainable and ecological construction that takes into account both environmental and economic aspects.

Kuittinen believes that his pilot project will trigger a trend that that will lead to more eco-friendly and sustainable forms of housing. Kuittinen also hopes that House Shadow will also encourage discussion and inspire other construction projects.

Kuittinen believes that the transition to a circular economy will provide significant opportunities for innovative and adaptable companies.


Practical implementation will virtually zero-emission steel

Matti Kuittinen's vision and SSAB's innovative solutions for fossil-free steelmaking are examples of how the construction industry can transition towards carbon neutrality and the circular economy.

House Shadow and SSAB Zero™ represent construction of the future. This project shows that the circular economy and innovative materials such as SSAB Zero™ can work together in creating sustainable and eco-friendly architecture.  

“We need to develop new ways of living safely and healthily in order to reach these goals. A tiny house could be one solution,” Kuittinen sums up. 


House Shadow generated attention at the New European Bauhaus Festival in Brussels

House Shadow, an innovative Tiny Home, was presented at the New European Bauhaus Festival in Brussels in spring 2024 as part of the Aalto University’s exhibition. This house is an excellent example of the application of circular economy principles in contemporary construction and received considerable attention from the distinguished public. House Shadow was the first exhibit a VIP delegation headed by European Commission President Ursula von der Leyen and Belgian Prime Minister visited at the fair. The week saw a significant number of interested designers, artists, researchers and construction professionals visit the stand.

Architect Matti Kuittinen, Professor of Sustainable Construction at Aalto University
Architect Matti Kuittinen, Professor of Sustainable Construction at Aalto University.

Building a tiny house is captured in a series of photographs. These images showcase the steps of the process by Aulis Lundell and the creativity that brings this tiny house, embracing the principles of a circular economy, to life. It benefits from SSAB Zero™ in the frame construction and parts of the façade, along with numerous other recycled solutions.

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The next generation of recycled steel

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What is SSAB Zero™ ?

SSAB Zero™ is steel made from recycled steel. It has near zero emissions during steel production, without mass balancing allocation of emission reduction or carbon emission offsetting.

Is SSAB Zero™ fossil free?

SSAB Zero™ is a near zero-emission steel in ironmaking, steelmaking and rolling, but not completely fossil-free, as the raw material is scrap. The recycled steel was originally produced with coal and fossil fuels.

How is SSAB Zero™ steel produced?

The first step in making SSAB Zero™ is to feed the electric arc furnace (EAF) with scrap. Heat is generated from an electric arc between electrodes. Oxygen is blown into the furnace, and lime and slag foamers are added to combine with the impurities and form slag. Molten iron is extracted and poured out via a tapping spout. Across the entire process, only fossil-free electricity and fuels will be used – resulting in SSAB Zero™ steel as the end-product.

When will SSAB Zero™ be available to the market?

The first launch of SSAB Zero™ steel products will commence in 2023 and the order of product roll-out will be defined by the requests from our customers. It is SSAB’s ambition to have a large range of our steel grades available. Your sales contact will be able to advise more specifically about your business needs.

As a customer, what are the advantages and disadvantages of SSAB Zero™?

The primary advantage of SSAB Zero™ is that it is a steel that has created near zero carbon emissions from fossil fuels in SSAB’s own operations. It leaves fossil fuels in the ground; this means that you and your end-users become part of an emission-free value-chain. The only disadvantage of SSAB Zero steel is that start-up production costs are higher, making it more expensive to produce and so it has a higher cost price.

How can I find out more about SSAB Zero™?

If you cannot find the information you are looking for here, please contact us here. Or get in touch with your SSAB sales contact directly.