Thatched Roofs: History, Performance and Possibilities in Architecture

The Wadden Sea Centre’s design by Dorte Mandrup seems to be a mirror of the natural landscape. Its low height and horizontal lines, as well as its materiality, make it a modern building that is in perfect harmony to the surrounding nature. Its connection to the local built heritage is enhanced by its straw-covered roof, which was harvested and dried near the ground. This is a very old and historical building technique that is seldom attributed to modern buildings. This article will provide some historical context, some examples and discuss some of its uses.

Wadden Sea Centre / Dorte Mandrup A/S. Image © Adam Mørk

It is difficult to research the history of thatched roofing. It is biodegradable and natural so there are no traces of it in older constructions. This is unlike stone structures or even rudimentary concretes. Researchers point out, however, that thatched structures date back to when humans became farmers and stopped living as nomads. Evidence of their use can be found in the Aztec empires, in the first buildings that we call Europe, and in research on its use in Europe and the UK, among others.

Itched roofing is a traditional technique that uses dry fibers like straw, reeds, and palm trees to make a roof covering. They are interwoven with a specific tension to create a surface that is impermeable and nearly impenetrable for rodents and other pests. Roofs are mounted from the bottom. The top of the roof needs to be maintained and taken care of as it can be a vulnerable point for water infiltration. A steeper slope roof will allow water to flow faster and prevent potential infiltration issues. However, this doesn’t mean the material is limited in terms of designers’ creativity. Flexible properties allow for organic shapes to be created, such as The Nest by Porky Hefer Design. The material covers the roofs and most walls.

The Nest / Porky Hefer Design. Image © Katinka Bester

Due to its multiple voids, surface irregularities and material composition, straw provides excellent insulation when dry. Straw is also very wind resistant if used correctly. Because thatch is light, the roof support structure may be less sturdy. Its behavior when lit by fire is another issue to consider. Because it is a highly flammable and dry material, you must take precautions to avoid combustion and control flames as soon as possible. There are currently companies that use flame retardants in synthetic fibers.

Kindergarten Zimbabwe / Studio Anna Heringer. Image © Stefano Mori

Because it is a relatively inexpensive and simple construction, it is often used in rural areas. This means that you won’t see thatched roofs anywhere in Manhattan or Sao Paulo. It is a unique technique that can be used when labor and materials are readily available. Studio Anna Heringer’s design for a kindergarten located in Zimbabwe is an example of this. It is part of the Permaculture Education Center in Zimbabwe. The project is based on the principle of self-sufficiency and was built in wood straw and stone. The project description states that the project uses local techniques to create a community of solidarity, team spirit, skills, knowledge, self-confidence, and dignity. Buildings, except when constructed from steel or glass, are not durable. However, it is important that knowledge and skills about how to maintain them and rebuild them be passed on to the next generation. (…) This project is primarily a training program in advanced building techniques using existing materials, which can then be composted from the kindergarten’s field.

Kindergarten Zimbabwe / Studio Anna Heringer. Image © Stefano Mori

Studio Morison’s Mother Pavilion was a similar approach. “The shape is a representation of the amazing hayricks that once dotted this country. (…) The roof and walls are made from local straw. The roofing was done in traditional style by a master craftman whose first job was to harvest a Haystack at this exact spot.

Mother Pavilion / Studio Morison. Image © Charles Emerson

This house in India combines the traditional method with more dynamic forms to capture rainwater. The thatched roof looks like an inverted pyramid, which descends into the courtyard. The courtyard doubles as a rainwater catchment and is not only a focal point.

Bapagrama Stone House / Pragrup. Image Cortesia de Pragrup

The ridge, as mentioned previously, is the most dangerous part of a straw roof. However, these are essential parts of all roofs. Wingardh Arkitektkontor AB addressed this problem by incorporating a skylight in the Facts Takern Visitor Center Project. The architects say that the building is covered in straw and camouflaged as a birdwatcher’s curtain to hide its contents from the natural environment around it. They are durable because of their steep tone. The gable is where a thatched roof is at its most vulnerable. It is now a glazed skylight.

Facts Tåkern Visitor Centre / Wingårdh Arkitektkontor AB. Image © Åke Eson Lindman

Straw can be used to create a contrast between tradition and modernity. The thatched roof at Sandellsandberg’s Synvillan Ericsberg Hotel and Nature Reserve contrasts with the straight shapes of the metallic cladding. Its reflective properties create the illusion of a house floating in the landscape.

Synvillan Eriksberg Hotel & Nature Reserve / Sandellsandberg. Image © Åke Eson Lindman