Hear Kathryn Larsen at Bæredygtigt Byggeproces talk about biobased materials

My goal is to show people the beauty and forgotten history of biomaterials

After coming across the Seaweed Houses of Læsø in 2016, Kathryn Larsen has been tracing the history of eelgrass and its uses in construction around the world. Kathryn Larsen is Architectural Technologist & Master of Architecture at Delft University of Technology, and at Bæredygtige Byggematerialer 1-2 September she will talk about different creative contemporary applications for eelgrass, straw, and earth, as well as some of the history behind these materials.

In this article, you can read an interview with Kathryn Larsen.

What is your background? And how do you work with biobased materials?

I am originally from the USA. My background is in architecture and architectural technology (bygningskonstruktion). I was always interested in traditional architecture, from the time I spent living in Japan, and looking at wood construction there. I started in architecture at Cornell University in the USA, and transferred to KEA Copenhagen where I finished my bachelor in Architectural Technology.

While studying at KEA, I looked a lot at traditional Danish building materials, especially how farmhouses used to be built. I ended up participating in lots of design competitions, where, for one concept I tried to come up with a new way of thatching eelgrass, inspired by the Seaweed Houses of Læsø and Vandkunsten’s Modern Seaweed House. I ended up developing this further for my thesis at KEA, and eventually designing several projects using eelgrass, while working full time in the Danish building industry.

However, because of my degree title, I was constantly limited in Denmark, as I was not seen as an architect or a designer by the industry. The options to continue studying, for example, to get a master’s degree or Ph.D. were very limited, and also would further complicate my path to permanent residency in Denmark. This is why eventually I left to do my master’s degree in Architecture at TU Delft, in the Netherlands.

Since then, I have continued my research/exhibition work with eelgrass and seaweed, in addition to studying full-time and working part-time for an interior design firm in Delft.

I recently went to Venice for a residency connected to the biennale, in the project “Non-Extractive Architecture” at the V-A-C Zattere. Here, I investigated the local seagrass population, and invasive seaweed species. I created a stool upholstered in invasive Venetian kelp that I turned into leather, and stuffed with eelgrass.

My master thesis will take my material experimentations to a new level at the TU Delft Explore Lab. I aim to study historical precedents for using seagrass and seaweed in construction, and seaweed farming. Then I hope to create a built prototype using different construction techniques for local seaweed species. I also would like to design this prototype from all facets, including furniture objects and interior design finishes.

What do you see as the biggest challenges in relation to biobased materials in construction?

There is an industry obsession with construction standardization, and a lack of research on biobased materials, despite us building with them historically for thousands of years. Recently, Realdania came out with a really interesting study on how biobased materials deal with moisture and self-ventilate in a construction (not to be confused with ventilating air through the building). I think we need much more research in this vein, and we need to be patient for the results.

In addition to this, the construction industry itself is very conservative towards “new materials” even if they are very old. One of the other issues is a perception that biomaterials mold or rot, or that they are less safe compared to synthetics- or that they are aesthetically unpleasing. I have heard people in Denmark scoff that sustainable buildings that are “mud huts” are nasty. As a professional, my goal is to show people the beauty and forgotten history of these materials.

What should we particularly pay attention to when building with biobased materials?

Building materials are in essence, sometimes trial and error over history. Research takes a long time, and changes or adds nuance to what we think is true or not. What we may think is safe and healthy based on “common sense” may actually not be good for us. Asbestos is natural mineral, for example, that insulates exceptionally well. But it’s also exceptionally dangerous to use as a building material. We should aim to study solutions and do test projects to ensure safety as much as we can, before jumping into mass production.

Also, the term “biobased” can refer to products that are wholly or partly derived from biomass, so they cannot necessarily compost. Some biobased plastics, for instance, need special industry conditions to biodegrade. The potential for greenwashing is high, and we risk simply replacing one issue with another, if we don’t consider other factors into the equation, like the embodied carbon footprint of certain building materials and the lifecycle of building materials.

Which opportunities do biobased materials create?

We have an opportunity to use materials that are not toxic towards local ecology and can potentially be disposed easier after a building’s lifecycle. This increases the likelihood that waste from the building will end up in the right place, as often times sealants, fire retardants, and glues are less likely used.

Sometimes plant-based building materials have a negative carbon footprint because they absorb more carbon dioxide than they create. However, this also depends on many different factors. If you’re shipping your biobased materials across countries for a specific project, the embodied carbon footprint of the material will increase. But the possibility of building low-carbon buildings is one of the biggest advantages in my opinion.

Can you mention 3 recommendation for how to move forward and use more biobased materials in the future?

More money for independent research projects and innovation in the biobased building material sector, a carbon tax on buildings, and more industry transparency of the carbon dioxide footprint of buildings.

The building sector likes to hide or manipulate its data, to claim freshly-built concrete and glass buildings are sustainable. They aren’t. The global building industry is responsible for over a third of greenhouse gas emissions, so it’s also our responsibility to do something about it.

Which projects with biobased materials do you find interesting?

I love the Wadden Sea Visitor’s Center by Dorthe Mandrup Architects, because it takes the art of thatching and applies it in a sculptural shape. To me, this is a great framework for how architects can reimagine the aesthetics of traditional building. I also like Feldballe Friskole by Henning Larsen Architects, because they’re utilizing Ecococon prefab straw elements. This is a really smart and affordable way to update traditional hay-bale building.

What do you talk about at Biobaserede Byggematerialer?

I hope to show a new perspective on how technology and design can apply to traditional biobased building materials and methods. Some might think of these methods as primitive, or conforming to a certain building shape or style, so I want to open people’s minds to the possibilities of how we can build in the future with these materials.

Do you want to hear more from Kathryn Larsen on biomaterials?

Join us at Biobaserede Byggematerialer 1-2 September. You can read more here and sign up here.

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