Can digital fabrication unlock a new frontier in low-cost timber construction? All signs point to yes in the IBA Timber Prototype House, a micro-architecture project that’s been playfully described as “a log cabin turned on its side” by its designers at the Institute for Computational Design and Construction at the University of Stuttgart. Designed to meet PassivHaus standards, the airtight and highly sustainable building system was developed as part of the International Building Exhibition (IBA) Thueringen and is currently on show in Apolda until September 29.
The IBA Timber Prototype House shows how computational design and fabrication technologies can turn low-cost timber construction into an environmentally friendly, economical and architecturally expressive way to build. The mono-material building consists of a series of staggered upright spruce timber frames with thin slits that serve as stress-relief cuts to prevent splitting and dead-air chambers to increase insulation values without compromising structural capacity. Digital fabrication and five-axis CNC milling also allowed for the creation of precision-cut airtight joints for connecting the timber elements so that no metal fasteners or adhesives were needed in construction.
“Conventional building systems have a vast array of different materials embedded in them, which often have very high embedded energy costs and are difficult to separate for recycling,” explains the ICD team. “In contrast, this research draws on traditional joinery, and a system was developed that relies purely on wood elements for structural connections and airtight enclosure, minimizing system layers and ensuring easy disassembly for end-of-life recycling. Furthermore, the project sources all the wood from within the state of Thueringen, where the demonstrator was built, allowing the team to minimize the embodied energy costs associated with moving materials over transportation networks.”
The tiny building’s curving walls and roof are also a result of digital fabrication, while simulations of the home’s energy efficiency—the house achieves a U-value of 0.20 W/(m^2K) without additional insulation—have indicated that the prototype should perform up to PassivHaus standards even during cold German winters.
Photos by Thomas Mueller