IBA timber prototype house. Credit: IBA – Thomas Mueller
By Shardell Joseph
A prototype log cabin combined with low-cost timber and advanced computational design and fabrication technologies has been built as a spin on micro-architecture.
Described as a log cabin turned on its side, the prototype is part of the international building exhibition (IBA) Thüringen, Germany, which opened on 24 May 2019. The IBA timber prototype house was designed and constructed by the ICD institute for computational design, using unconventional techniques to create cost-effective and eco-friendly mono-material building envelopes.
Unlike typical log construction using horizontal stacking, the cabin has been arranged with solid timber elements as staggered upright frames. The vertical elements are aligned in the strong direction of the wood – this allows sawing slits in the solid timber without compromising its structural capacity.
The slits are an imperative component to the structure acting as stress relief cuts, which prevents the solid timber from splitting. Not only do the splits ensure dimensional stability and airtightness, but they are also utilise as dead air chambers, reducing thermal conductivity and increasing insulation values of the material.
To then connect the timber elements, ICD have used digital fabrication to produce high-precision, airtight joints. This removes the need for any metal fasteners or adhesives.
Using fully integrated computational design tools, a direct conduit was created – from design geometry to machine code data for driving automated fabrication tools. This geometric variation creates shifts and offsets in adjacent beams to follow the gently twisting and curving walls and ceilings of the designed building envelope. The digital tools not only offer the possibility to maximize the ratio between available space and envelope surface, but also intensify the architectural experience of this unique structure.
The use of computational, design-to-fabrication workflow allowed the researchers to iterate geometric forms quickly and also understand the consequences of design decisions regarding building metrics, fabrication time, and material usage instantly. According to the researchers, the workflow successfully integrates design, engineering, construction and material sourcing which overall improves standard architecture practices.
IBA will be using the timber prototype house as an exhibition as well as a meeting and exhibition space, showcasing the cabin as they claim it is proof of the possibility for innovative design research that is still based on regional materials, knowledge, industry and labour. Simulations have indicated that the demonstrator should perform up to Passiv Haus standards.