The Prefabricated House

An architect’s search for the future of American architecture.

Brett Holverstott
Mar 1 · 7 min read

As a designer, I often wonder where things are going, where serious architecture will be in another decade, or two, or three, independent of meaningless fads in colors or materials.

I would like to help drive the change with innovative, and great, contributions to the architecture of our time. I haven’t achieved this yet, but if I let my reason and emotions guide me, I will be on the right path.

New impactful design is more than just aesthetics, it requires technical innovations that lead to new breakthrough possibilities. And that innovation takes work. It is not just one thing in isolation, but a bunch of solutions that build on one another, guided by an asthetic vision.

In my career of about a decade, I have been motivated by the innovative strides of relatively unknown figures who are doing the hard work of improving the way we build.

When I was still earning my degree, I heard a talk from guru Katrin Klingenberg whose small 1,600 square-foot home was the platform of her advocacy for U.S. adoption of the Passive House standard of bulding energy efficiency being developed in Germany.

Klingenberg’s home had two layers of wall. The outer layer, made up of cellulose-filled boxes, was the primary envelope. An inner layer of traditional framing acted as the primary load bearing part of the structure and allowed electrical and plumbing to be run through the wall without interrupting the outer layer.

I loved the thick walls, solar oriented design, controlled continuous ventilation, and the idea that this was a permanent solution to energy efficiency (a huge reduction over code) that would last for the life of the home. I didn’t want to ever build any other way.

It was also not lost on me that Klingenberg prefabricated her insulated boxes before erecting them, and then framing a house on the inside of her envelope.

In my late twenties I quit my job to study Klingenberg’s Passive House method and design a house for my first clients. My understanding of how light, heat, moisture, and air moved through the envelope of the home — what we call ‘building science’ was suddenly beyond that of many architects I knew. On my first project, I was training my seasoned builder in how to do something new, and we learned lessons along the way.

During this time I shared the office of architect Susan Jones, who was pioneering the use of a new material called cross-laminated timber (CLT) in her projects.

CLT is made up of layers of solid timber glued on one another crosswise to create a flat slab or wall of solid wood. It is prefabricated in large factories and comes predrilled with penetrations for utilities and precut to allow windows and doors.

Susan’s home in the Madrona neighborhood of Seattle demonstrated the elemental beauty of large smooth surfaces of wood lit from above by large windows. Jones also found use for the material in sacred spaces.

But moreover, Jones has been doing the hard work of advocacy and changing building codes to accept this new material and its structural capabilities. I remember one round table discussion in which we used origami folding patterns to explore the use of CLT panels for a cathedral-like space.

Later, while attending a conference in Seattle at the Northwest EcoBuilding Guild, I heard a talk from genius-level American timber framer Ted Benson who was developing a new prefabricated system for home building, called Unity Homes. The idea was to fabricate panels for walls, floors, and roofs in a factory and assemble them rapidly on-site in a matter of days, from fifty or sixty pieces.

Benson was using grids to help speed the design process (a trick used by Frank Lloyd Wright), which had the added benefit of allowing the design of reusable modular elements (such as kitchens and bathrooms, bay windows or stairs) that became standardized parts and pieces that could be assembled in the modeling software into a custom product.

Custom design from standard modular units.

Bensen had a systematic philosophical approach to building homes able to last generations, and he utilized many principles of Passive House design.

Bensen’s recently retooled his factory to allow his crew to prefabricate panels in an assembly line, assisted by European machinery. This factory serves not only the Unity Homes line, but the sister company Tektonics which builds and delivers custom fabricated panels for any kind of project.

Again, I was hooked. The idea of assembling homes from prefabricated components gripped my mind with aesthetic possibilities, nevermind the many potential commercial advantages of prefabrication including quality, durability, cost, and speed.

I wanted to get involved in prefabrication and soon I found a position with Christian Gladu, a master craftsman and designer who was an influential pioneer in the rejuvination of the American Bungalow movement, but was now reinventing his pratice in collaboration with a modular builder.

The Bungalow home, developed in the 1930’s, was an indigenous response to smaller walkable urban communities. It was also a response to factory prefabrication of building elements. Sears kit houses allowed every piece of wood to be precut and numbered and shipped by train to the jobsite for do-it-yourself builders.

When Christian started the Bungalow company, one of the first stock plan companies on the internet, he updated and perfected this building type and had a vision of integrating prefabrication into the system, which was never fully realized. He has recaptured this lost dream by learning the ropes of designing for prefabrication. For the last two years we have been working closely with a modular builder, Greenfab Homes.

This aint your grandaddys modular, but is a new market sector for custom, higher-end modular homes.

Modular homes are prefabricated as finished boxes and set on site with a large crane in only a few hours. These boxes can be huge, up to 65 feet long. And while there are more dimensional constraints in the system, the rules can be intelligently broken if a project needs a custom solution. If done properly, the majority of work on a project, from framing through painting, occurs in the factory.

As a designer I have found working on these projects riveting, because it is a process of exploring what is possible and inventing new technical solutions, the real hard work of making prefabrication work.

Small, boutique modular shops (Greenfab, Method, BluHomes, PlantPrefab, Modescape, etc) are springing up on both coasts. Instead of competing on the basis of cost in suburban tract developments, they are selling an experience to younger and more urban clients, who want their home delivered to them in a white box like an iphone.

They are willing to pay what it would cost to site-build a home, or even more. That’s a business opportunity, but it is being pioneered by industry outsiders, not established craftsmen.

“Clients want their home delivered to them in a white box like an iphone.”

Larger modular shops tooled to prefabricate large, multifamily buildings are rapidly gaining industry traction as they have a much more clear path to profitability. FactoryOS is one example, and softbank just floated Katerra with a cool billion. Change might happen through brute force of venture capital.

While traditional modular has always targeted more historical designs, the new modular is grouping around a new kind of international style modernism that uses the box for its aesthetic interest. Like postminimalist sculptors facinated with compositions of stacked boxes, architects are finding new spaces where boxes stack, cantilever, and split apart.

While it is fun to play with boxes, flat roof boxes without eaves are more susceptible to overheating and water penetration. The international style always had too much glass, reaching (at worst) a kind of wall nihilism. We see some of that with the new modular, driven by the complication of adding eaves — a problem with which I am now intimately familiar.

It is an aesthetic that people like, that is sellable in the marketplace, and it is ready off-the-shelf. But in this way it is similar to a historical style. It is a reinterpretation of a now nearly century-old avant garde. Maybe we are still in a formative period where prefab is finding out what it can be, while architects struggle with the technical details of making it work.

Innovation is all about moving small technical solutions forward in the context where they make sense.

For example, in one modular home we used a CLT slab as the floor. A 5–1/2" thick slab can span the same width of a module, and act as both a beautiful wood floor and a ceiling for the module below. It was a smart response to a specific zoning height problem, and simplified the building. But it complicated the deployment of the project, by requiring a temporary ceiling on the lower module.

However, this small move is potentially the source of new aesthetic possibilities and usefulness. CLT can act as a two-way span able to cantilever a module from a lower structure in two directions. It has a natural fire resistance that allows it to separate a primary dwelling from an accessory dwelling. It has thermal mass that can aid in the stability of interior temperature.

When a new innovation is introduced, it often seems to generate more problems than it solves. I may need to develop an inflatable (pneumatic) temporary roof system to protect the lower module.

The whole rising industry of custom home prefabrication is generating more problems than it is solving, but it holds a promise that is exciting builders, designers, and homeowners.

The ‘Promise of Prefab’ is a product that is manufactured more quickly, to higher precision, in a dry controlled environment, with more skilled labor, assisted by machines, organized by a factory process, supported by an international pipeline and staging for supplies, but responsive to the needs of individual clients. And ultimately — a better quality product at a better cost.

For the moment, it will need to struggle with the complications of fabrication, connection, rigging and setting of homes.

I look forward to inventing fresh new moves that lead to new possibilities in design and emotional experience. It will be an integration of new materials, ways of building, and standards of quality. It will help bring about the future of architecture.

Brett Holverstott is an architect in Seattle, Washington.

Brett Holverstott

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Philosophical writer on topics in science, art, and technology. Practicing architect in Seattle.