Ecological construction is a part of the present and the future. But a house made entirely of reeds on the shores of the bird sanctuary Lake Tåkern demonstrates that ancient techniques in innovative design can also work for present-day and future sustainable buildings.
“Reed is an amazing material,” says the architect Jonas Edblad from Wingårdhs who designed the recently inaugurated Naturum [Visitor Centre] on the shores of the bird sanctuary Lake Tåkern.
A house covered entirely with reeds, in a sculptural and futuristic design - but built using a thousand year old technique not normally used in contemporary architecture. But it should maybe be used more often, as reed as a material is very suitable for ecological construction.
“It was when we found out that Lake Tåkern has one of the best reed beds in Sweden that we realised we had access to a very exciting material, and obviously worth investing in,” he continues.
Naturum is an exhibition and inspiration facility, located in a beautiful, often unique protected natural environment. It is based on a unique Swedish concept that the Swedish Environmental Protection Agency initiated many decades ago, and there are now about 30 of them. From Abisko in Lapland in the north to Stenshuvud right down at Skåne's southern tip. Naturum is not renowned for any particular prominent architecture, but prior to the recently inaugurated facility at Tåkern, an architectural competition was jointly organised with the County Administrative Board in Östergötland, which was won by Wingårdhs Architects in Gothenburg. Using thirty million reed straws to clad the building entirely was indeed the most characteristic feature of the winning proposal.
For anyone approaching the building along the wooden walkways, randomly located through the edges of the woods, it pops up like a sturdy and solitary monolith just where the view widens, providing a panoramic shot towards Omberg on the other side. From a design perspective, the building is similar to a cut diamond, although the surface of the reeds provides a compact and matt finish, and a rather dull tone. Its silhouette is characterised by steep, irregular roof tops with numerous angles and deep cut-outs, where light comes in. It is a genuine gem, even if it is made using a material that is considerably more porous than that used previously.
Jonas Edblad is more inclined to compare the building to a bird. He thinks that the organically shaped, smooth hugging exteriors remind one of a bird's plumage.
The irregularly-cut shapes - very much in keeping with the organic and digitally based mindset within architecture for the past few decades - are directly dependent on the material's specialised properties. If a reed straw building is to last, it cannot retain too much moisture. Steep roof valleys are therefore a must to allow any water to drain off. The aim within the reed construction industry is that at least 45-degree angles are required to preserve the material for between 50 to 70 years.
The technique used involves placing reed bundles on top of a load-bearing wooden structure. Each straw is hand cut and the technique where numerous bundles are used means that the exterior can be easily maintained. Each bundle can be replaced without having an impact on the rest of the exterior wall.
Reed is also a naturally insulating material, corresponding to approximately 10 cm of conventional insulation. Moreover the technology and framework used is based on the experiences from passive energy houses - a well-insulated and airtight climate shell combined with mechanical ventilation and efficient heat recovery. Normally, this reed building is expected to work without any heat source other than that generated by the building itself.
“A key element in ecological construction is of course the use of locally available materials,” says Jonas Edblad. “In addition to reeds from Tåkern, we have used limestone from Borghamn in the floors, as well as glass and locally-produced timber products for the carpentry work.”
Straw plants such as reed and bamboo are among the world's oldest and still most widely used building material, especially in the tropics. One advantage is that they are easy to build with. They provide lightweight structures with good ventilation, which are easy to maintain, and can also withstand earthquakes. The materials are cheap, and tools and craftsmanship have been developed down through the ages.
One disadvantage includes the risk of fires, about which Jonas Edblad has already received numerous enquiries. He maintains that this fear is exaggerated. Experience indicates instead that the traditional Swedish thatched roofs - a common type of reed construction here - do not burn down very often.
“Reeds are often full of so much moisture that they cannot catch fire,” he explains. “If someone tries to set a match to them, they usually glow like a cigar, allowing for the danger to be discovered in time.”
In Sweden, as in other Nordic countries, we have mainly used reed straw for thatching roofs. Reed roofs are still common in and characteristic for southern Sweden, not least in Skåne. They have been maintained by an ever dwindling group of skillful thatchers, who in recent years have had more and more to do. Interest in Swedish thatched roofs is on the up, and several new ones have been constructed.
However the use of reed in modern architecture is few and far between. On the other hand, the attitude in Holland is more experimental. Both traditional roofing and more innovative straw structures can be found. Even the Danes have an apparent interest in reeds and straw as materials for use in contemporary architecture.
In addition, in today's global eco-architecture, there is a steady increasing passion for other locally based, ancient building techniques, and not just using reeds and bamboo. The diverse flora of ideas for tomorrow's green architecture comprises inspiration from the Icelandic tradition of covering entire houses with normal grass, from mud houses in Syria, yurts in Mongolia, igloos in Greenland and cave houses in Southern Europe.
But the architects at Wingårdhs in Gothenburg are satisfied with the new reed building so far.
Sweden also has its own exquisite and futuristic building made using this simple and traditional straw material.
“This kind of material has definitely whet our appetite,” says Jonas Edblad.