Hope from Wood Blog Series, 2021

Charlotte Bofinger: Hope from Reuse

Last summer, the extension to Hall K118 in Winterthur was completed. The three-story extension has since then caused quite a furor. Approximately 70% of the building was constructed from recycled materials, clay, straw, and wood. The declared goal was to reduce grey emissions through this type of construction and thus minimize the CO2 footprint of the building.

That because the construction sector is one of the biggest emitters in the world. 40% of CO2 emissions, 50% of waste, 90% of the consumption of mineral resources. The climate crisis is undeniable. To reduce these emissions, the entire construction branch must go new ways. At the same time, it gives us as professionals in the building sector the opportunity, on a comparatively small scale, to develop and demonstrate solutions that can then be scaled up. In this way, hope can be generated personally, which then draws circles and gives other people courage to follow similar transformative paths. Hope from Wood and Hope from Reuse thus become courage for transformation.

Where we come from and where we go to

K118 and Zirkular did not come out of nowhere. We are, so to speak, the youngest child in a family of four offices. ”Unterdessen” ensures that empty spaces are used intermediately, which leads to fewer demolitions. ”Denkstatt” develops spaces with what is there for what the people on the spot need, and thus has a transformative effect.

And then there is the ”baubüro in situ”: a somewhat unusual architectural office. Founded 20 years ago with a focus on transforming existing buildings and industrial sites with minimal interventions. Since about 10 years the office gains experience in temporary structures, like schools and housing for refugees. In the last 5 years, baubüro in situ AG has strengthened another core area: Reusing not only existing buildings, but also making new buildings out of existing building components and materials.
Based on these experiences, Zirkular was founded in 2020. With the idea of deepening the expertise and contribute it to many more projects with other architectural offices. Specialist planning for reuse is our core business.

Not only the buildings change when they are built with reused components, but also the processes and thus the tasks and professions.

Repairing, for example, takes time and brings local added value.
Resource- and climate-friendly construction creates new images.
New job profiles, too!
In our office, we employ component hunters, have construction managers for recycling-friendly construction and have become re-use experts and supply chain managers.

These activities are new territory, cost energy, are meaningful, forward-looking, and often simply fun.

Decarbonizing the construction industry and transforming the linear economy into a circular one.

We all know the curves that show us how drastically we need to reduce our emissions in the next few years. Switzerland should be climate neutral in about 7 years. Of the 40% of emissions for which the construction industry is responsible, about half are generated during the construction of buildings. Grey energy and emissions that are then ”stored” in our buildings. But Europe is already built, the situation is different when you look worldwide. In Europe have all the materials we need already accumulated in our buildings. We can see this as an opportunity. We already provided the starting energy in the last decades and the building booms that went with it. What was created there we can now use, transform, redistribute. Redistribute in the sense of dividing space among people and in the sense of circulating materials. Then many energy-intensive steps such as primary steel and cement production would simply be eliminated, at least to a large extent.

This leads to the second point: the challenge of turning the linear throwaway economy into a circular economy. this is anything but easy, because we have been building for the waste economy for the last decades. But it can be done.

There are two principles for winding up: 1. to directly reuse old material and 2. to build in such a way that reuse is easily possible at the end of use. At Zirkular we do both. But we place the most value on the first step, because only then do we save emissions today, and that is what counts.

There is a lot of material that is deconstructed but no established structures to bring it back into the cycle. We are creating this from scratch, it is part of the rewinding process.

Emissions are emitted during the production of a material and the construction of a building. The atmosphere is polluted. The emissions are attributed to the component as grey emissions. If the component is used for the next application instead of being thrown away, no new component must be produced and therefore no new emissions are generated. Of course, the balance is not zero. The less transport, storage and reprocessing are necessary, the less emission add to the reuse component. The higher the savings compared to a component made from recycled or primary raw materials.
With wood it is a special case again, as trees are known to bind Carbon from the air. However, a tree takes a long time to grow, and the effect on the atmosphere is only achieved when the tree has grown back. After all, a tree in the forest also binds Carbon. If a tree is built into a house and another tree grows in its place, it takes 60-100 years until the Carbon is bound from the atmosphere. It depends a bit on how you look at it; it gets more complex with whole forests.

Nevertheless, if a beam from an 80-year-old house is reused, the tree has already grown back, and the CO2 storage effect can be extended. Only if the wood as such is preserved does the carbon remain bound.

Three examples of reusing Wood

Artists’ studios in the former Gasworks Schlieren, 2021
Reuse was the first choice for the conversion of studios in a listed former gas power station. Due to the requirements for the preservation of historical monuments, everything had to be planned reversibly, and the service life of the fixtures was only 10 years. The consequences: a project that relies almost exclusively on the reuse of building components. The wooden windows that are hinged on the inside come from a block edge housing estate in Zurich, the wall and ceiling construction made of wooden panels originally served a temporary railway crossing in Winterthur and the wooden slats were the railings of a road overpass just a few months ago.

Conversion of ELYS Kultur- & Gewerbehaus, Basel 2021
Deconstructed wood is usually ’thermally used’, i.e. burned. For the façade in Lysbüchel, purlins, rafters and glue-laminated beams were collected from deconstructions in the surrounding area, sawn into lamellas in a sawmill and used to produce torsion-resistant glue-laminated beams. In contrast to the previous construction timber, the glue-laminated beams then meet the high requirements of timber frame construction.

EMPA – Unit Sprint im NEST Dübendorf, 2021
The nest at EMPA is a research building into which building boxes can be inserted for research. With the sprint unit, office space was created from Reuse components and materials in a very short time. As long as individual offices are needed due to the pandemic, reversible walls made of carpet tiles, books and roof tiles with clay mortar separate the offices into two halves. The permanent partition walls of the office units are created from material sections that accumulate during standard timber modular construction. In today’s construction industry, these sections (pieces of Fermacell panels and 3-layer panels) represent a constant stream of material that can be accessed at any time. The wall system developed by Baubüro in situ meets the usual fire protection and sound insulation requirements and the interior wall can be produced by the meter, so to speak. The load-bearing timber construction of the office units comes from sawn-on beams of a deconstructed roof structure.

We are always trying new things because we believe that it is possible to build and live differently. And because it is fun.

Charlotte Bofinger, Zirkular, 28.03.2022, Basel

Published 11.04.2022

Charlotte Bofinger 

Charlotte Bofinger studied civil engineering at the University of Stuttgart. She has been working at Zirkular since May 2020. There, her knowledge from her Master’s degree with a focus on modelling and simulation, several years of experience with challenging reinforced concrete buildings in Switzerland and several further training courses and self-study on regenerative building all flow into one another: in search of a way to build in accordance with the planet’s boundaries. She is a co-founder of the Rethink Materials collective and is heavily involved with Architects for Future Germany.