MASS-PRODUCED HYGROSCOPIC ENVELOPES:THE NAUHAUS

Traditional systems are great, but, let’s face it, times have changed. Our buildings have a more complex job these days as they are asked to provide a very stable interior comfort zone complete with running water and wireless internet. Also, mass production has lowered costs. If you don’t believe me go out and price a thatched roof compared to a high quality standing seam metal roof. And when it comes to financial and environmental impact, the materials themselves are only a small part of the story. It’s the operation of the building (heating, cooling, and plug loads) that is responsible for most of the resources a building uses through its life. Still, we don’t want to throw the baby out with the bathwater. Can we maintain the core wisdom of indigenous systems, which in my estimation is low-embodied energy materials and passive design tailored to microclimates, while tapping the benefits of mass-production and advanced building science? The Nauhaus Project was conceived as an attempt to do just that. The project was designed to the Passivhaus standard, probably the most rigorous building energy standard in the world which requires very careful design of an airtight thermal-bridge free envelope that allows a lower impact mechanical system and provides superior indoor environmental quality. The wall system, however, was intended to emulate many traditional systems in that it utilized mass in a hygroscopic assembly. The material chosen, Hemcrete, was made from a waste material (shiv) but engineered, packaged, and sold as a mass-produced product allowing for quality control and accurate cost estimation. Site-made materials were used when they fit the performance goals. Interior floors and mass walls are compressed earth block made on site and the interior is plastered with a variety of earthen plasters. Many innovative systems were incorporated combining simple passive technologies with high performance mechanicals. The design minimized interior square footage with extensive use of outdoor rooms creating an incredibly comfortable living space that can be heated by the body heat of ten people on the coldest day of the winter in fairly cold climate (Asheville, NC).

Nauhaus Animation
Why Nauhaus?
Description of Passive Systems in the Nauhaus
WHY?
I grew up in the intense heat of Central Texas where everything living is in a constant search for shade. Whether a cow under a tree or a dog under a porch, the rationale was consistent and obvious. This logic was carried through by us humans in the older neighborhoods where houses with large front and screened back sleeping porches were nestled under the spreading canopies of oak trees clearly older than the houses themselves. This changed. Maybe it was the arrival of air conditioning and the money to be made by replacing trees with more houses. Whatever the reason, newer neighborhoods were treeless and porchless and HOT. The contrast was stark and unequivocal. The newer neighborhoods (tellingly relabeled “developments”) locked in a dependence on fuel driven, breakable mechanical systems and set a hefty baseline energy usage. They also defined two completely distinct environments, with the inside becoming a sort of prison of comfort discouraging inhabitants from venturing outside as part of their daily home life.  The older neighborhoods, on the other hand, used passive strategies (trees, overhangs) to adjust the microclimate around the buildings toward the human comfort zone, lowering cooling loads and therefore baseline energy demand while creating a “third environment” around the house that encouraged a lifestyle that included being outside.. I didn’t realize it then, but this was my first lesson in passive design and it set the tone for my future work in sustainable design. Though I see mitigating climate change as a central macro-rationale for my work, I believe that the sensible path to efficiency leads to a better, healthier lifestyle. Over the years I’ve gotten deeper into science of building envelopes and increased the scale and scope of the projects and materials that interest me, however the throughline in my research has remained constant and can be described by the motto: passive first, then active.
WHAT?
I conduct research into materials, assemblies, and systems in the context of building envelopes. I am particularly interested in high performance assemblies and how to configure them so that they interact with site conditions to minimize heating and cooling loading while maximizing durability. My associated research life has comprised essentially three phases: (1) site harvested and waste materials modeled on traditional hygroscopic systems; (2) mass produced materials and assemblies that increase functionality within the existing construction industry while maintaining certain benefits of traditional systems; and (3) concrete technologies, specifically with the goal of improving concrete’s carbon footprint and maximizing its thermal performance potential in building envelopes.
HOW?
I generally try to connect all research I do to a design project and connected publication. Sometimes this cycle has been very personal. For example when I lived in a two room mountain log cabin for three years and took a self-directed course in homesteading. Most often it has been tied to residential design and publication projects. As my interests have moved toward the larger scale and industrial, I have moved into a traditional academic lab research and journal/conference publication paradigm.