A conversation with Spinneybeck introducing Søuld

30 / 08 / 2024

We talked with Spinneybeck about our founding history. Read highlights from the interview here and learn, why we fell in love with eelgrass, how it is connected to the tiny Danish island Læsø, and what impressive features the natural material eelgrass possess. Spinneybeck is asking the questions, we answer.

Q: Tell us about how you came to found Søuld!

The foundation of Søuld is closely linked to the little Danish Island Læsø, where eelgrass historically was used as a thatching material. The legacy of the remarkable roofs was close to being forgotten in 2010 where only few of the historical houses were left. Our first activities were to preserve and learn the old thatching technique as well as restore and rebuild the lost houses on the Island. However, there was a gap between the cultural heritage of using 60 tons of eelgrass for one roof and the modern way to use optimized building materials. A new design language had to be invented to elevate it from its original use.

The initiative for Søuld was taken by my architect colleague Pi Fabrin and me, Tobias, two sustainable design engineers Gunnar Agerskov and Kirsten Lynge and Læsø based eelgrass thatcher Henning Johansen. We established Søuld with a shared mission to contribute to the development of sustainable design and construction practices by providing sustainable alternatives to traditional building materials.

Q: What initially attracted you to this material?

Personally, my journey started in Barcelona at the school of architecture where I was looking for a material that could turn buildings into a host for nature. A material that could make natural life a physical part of our cities. Quite fast it led me straight back to my home country Denmark where the historical houses on Læsø showcased that nature really can be involved and interact with buildings. It also showed that a material like eelgrass can last more than 300 years on a roof. I thought that developing eelgrass products would be exciting because it would have such a strong relationship with where it comes from – the sea.

Q: What are the inherent qualities of this material that excited you?

Eelgrass is an extremely robust material. History has taught us that it can stand more than 300 years exposed as roof material. I get drawn to the material because of its scale, aesthetic and tactile qualities – a material that I need to touch. Technically eelgrass is naturally fire-impregnated with minerals from the sea and is both insulating and sound absorbing. Last but not least eelgrass could be the ultimate climate material as it absorbs enormous amounts of carbon as it grows. Eelgrass even absorbs more carbon than we are using in our production to make our final acoustic product. As an architect and engineer I was quite overwhelmed by the potential of this material as it’s a natural waste material and just washes ashore – ready to be picked up and processed.

“We established Søuld with a shared mission to contribute to the development of sustainable design and construction practices by providing sustainable alternatives to traditional building materials.”

Q: How does sustainability drive other areas of your company and production?

Eelgrass is a plant that grows in meadows in shallow waters – it is not an algae, but an underwater plant. Fish thrives where it grows, the water is cleansed, and CO2 is stored in the sediment. Eelgrass meadows provide marine ecosystems with a range of services and must be left undisturbed. During the growth season the leaves will detach from the plants and many of the leaves will end up at a nearby coast. This is where our farmers pick up the yet green leaves – instead of letting them decompose along the coast. By removing ‘left over’ biomass from the marine environment, nutrient is also removed. When eelgrass is dried on nearby grass fields the carbon in the leaves is preserved instead of being released into the atmosphere. The carbon is then stored in the long-lasting products of Søuld.

Q: What trends in the design world are you seeing in Denmark that are sparking your interest?

I see a general awareness of raw materials being less processed. Designers celebrate the materials by keeping them as natural as possible. This allows the natural colors and tones to arise in the different designs. Many of the Danish design brands have been well known for its pure lines, lightweight constructions and use of light toned materials, such as oak, beech and paper cord since the 1950's. Modern Danish designers are not afraid of using dark wood or voluminous organic shapes.

Q: Are there any trends regarding sustainability that you're noticing specifically?

There is a lot of focus on a product's climate footprint at the moment. Especially when delivering materials to building projects in Denmark and the rest of Europe, more and more projects demand that you have a 3rd party verified Life Cycle Assessment. We have that as a part of our Environmental Product Declaration (EPD). Here Søuld really has an advantage, as we perform really well. Other good and biobased products might have a climate footprint that compares with Søuld’s, but many of them lack good performance on acoustics and fire. This is really what makes Søuld unique.

Q: Can you tell us about the environmental impacts on eelgrass over time? How does the material change from year to year? (Color, density, etc.)

Over time eelgrass fibers become lighter when exposed to light, just as untreated wood planks. The beautiful play of colors from fibers with slightly different tones will become more conspicuous.
Another feature that most people do not think about is that the eelgrass fibers can absorb and release moisture in a room. This has a notable effect on the indoor environment. As Søuld does not contain harmful substances or chemicals this ‘lung’ of the room will not release strange compounds to the air but can contribute to a more balanced indoor climate.

Q: What are some of the common questions that came up as you introduced the material to designers in Denmark?

As we are introducing a natural material it will come in a natural color. Many designers love the material, but some will typically ask “so does it come in white and how can you guarantee that I get the same color next time?”. Personally, I love the natural look of eelgrass and how it varies depending on the beach it came from, which time of the year it was collected and how it beautifully ages over time. When you are working with natural materials, I believe that you should celebrate the beauty of imperfection and variations.

We are introducing eelgrass as a new raw material for the acoustic market. So, a typical first question would be if there is enough eelgrass. Eelgrass grows in most parts of the world, and you would be surprised by the amount of leaves that are floating around. For instance, one of our farmers told us before he started that there would only be very little eelgrass at his coast, but after a year he collected more than 100 tons of dried eelgrass on a 50 meters beach. He has now been working full time collecting eelgrass for 15 years.

Read the full interview here →