BY BRIAN LIBBY
Over the past decade, prefab architecture has steadily gathered attention and investment, with the chintzy sheet-metal-clad, mass produced trailer-park homes of the previous generation giving way to high-end architecture that’s factory made but thoughtfully designed by architects like Frank Genry disciple Michelle Kaufman.
Besides just single-family residences, prefab is increasingly being embraced for multifamily housing projects and commercial architecture. It’s perhaps inevitable given prefab’s substantially lower construction costs, a quicker construction schedule, better quality control and less waste. There are various forms of prefab and modular architecture, and it can, with the help of some kind of architectural structural framework, grow to the height and density of skyscrapers, such as with the 32-story residential tower under construction in Brooklyn’s Atlantic Yards development (which also includes the Barclays Center arena). But most multi-unit prefab housing projects are decidedly smaller.
This medium-density prefab was the topic of a University of Oregon architecture class’s final projects, which I checked out a few weeks ago at the invitation of professor William Macht. Macht assigned the prefab housing class to design housing that is “intended to be flexible in development and ownership, either by a single owner, multiple owners or collectively. The density, at 32 units per acre, is intended to go beyond ADUs but not to high-density. This should also permit an alternative infill development pattern both within cities and more urban fringe and suburban areas,” he explained by email. The idea of different sized units is to permit people of different ages to live in close proximity, whether unrelated or in an extended family. Age segregation is a large and growing problem.”
Set aside the notion of prefab for a moment and consider the broader land-use context. With continuing city and state goals for limiting sprawl and adding density via urban infill, it is often multi-family condo and apartment buildings that get the most attention and even sometimes controversy when such structures abut neighborhoods of single-family homes. We see headlines of such battles regularly, be it projects on Division Street or Williams Avenue to name two recent examples. But between these housing types is another a variety of medium density architecture that often goes overlooked but is an important part of the real estate market.
Into that equation, prefab has made modest progress, Macht believes, but none have truly been able to move far beyond single orders into broad mass production, where the profits lie. Existing models bear the added cost of transport of units on oversized vehicles at great expense as wide-load cargoes with lead and trailer cars needing expensive cranes at the site.
Even so, particularly at medium density Macht believes prefab could be a way to build flexibly: adding as much as one can upfront with the option to add units later. It can also provide opportunity for extended families of different ages and generations to live together. More importantly in a region like ours with density borne from land-use laws restricting sprawl, the more efficient use of space multi-family prefab can bring can aid in that process. “Planning policies still overwhelmingly favor single-family detached houses with mandated front, rear and side yard setbacks,” Macht says. “A typical 2,000 square foot, single family detached house occupies about 1,000 square feet of land on a parcel of at least 5,000 square feet. Therefore the footprint comprises 20 percent or less of the land area, leading to housing sprawl.”
Obviously many people cherish their yards, and having some distance from their neighbors. But not all can afford that. Clustered prefab units stopping short of full-on condo or apartment buildings have a place in this market, perhaps especially in suburbs.
For the final project in Macht’s class, each student was asked to adapt an existing system, or propose an alternative system, for the design of four units of different sizes (500, 1000, 1500 and 2000 square feet, respectively) on a standard 50-by-100-foot city lot. They also had to come up with one parking space and private outdoor space for each unit; in the case of outdoor space, it could be combined into one common space. The total estimated development cost including land and system development charges, was not to exceed $200 per square foot.
I was there along with a small group of architects and a developer as part of a critique of student projects, although I felt as if I was learning more from the students than they’d learn from my comments.
Their presentations encompassed the range of modular types, which have to do with how much a unit is assembled before it gets loaded onto a big truck for delivery to the site. Some students chose versions almost entirely factory made, others designs with the walls and floors. One interesting aspect of this medium-density housing type is that it seems to pull the designer either in the direction of a single-family home or a larger multifamily building as its inspiration. Only some of the students seemed able to create variations on stacked modular units. Most simply arranged the long blocks of form on one side of a lot or another, just varying on how they divided up outdoor green spaces and parking spaces. But a few seemed to grasp three-dimensionally the idea that in the most efficient designs the roof of one unit becomes, say, the garden patio of another.
I also took interest in the non-architectural precedents and inspirations the students incorporated into their designs. One used the game Tetris, likening the arrangement its differently sized falling blocks to fitting various configurations of building onto a lot. Two other students used self-assembly kitchen shelving as inspiration, in which shelves snap on to metal poles for support.
For those students or architects looking to work in prefab, the job requires a different skillset and business model. One has to be more of a problem solver, particularly as it relates to space: these have to fit onto trucks to be transported. And with the added cost of transportation, reducing cost without compromising material quality is paramount. Even so, prefab and modular offer architects the chance to design for clients or to sell their own.
“It’s not for everybody,” says architect Stuart Emmons, who was part of the jury critique group for Macht’s class (and with whom, in full disclosure, I worked on the Coliseum campaign.) “It works for some things and it doesn’t for a lot of things. I don’t see myself as a traditional architect any more. I see myself as a quasi developer and provider of units. It’s a different way of designing, a different mindset. It’s almost backwards in some ways and forwards in others. It gets very technical. I guess the other thing is everything has to be figured out before hand. It’s like an industrial design product. That’s a very different animal than what architects are used to. I think it will slowly come in more in the United States, but Japan is way ahead of us. So are Sweden and Holland and other countries. We’ll get there.”