October 1, 2008
The Promise of Prefab
John Quale is an assistant professor at the University of Virginia School of Architecture and the project director of ecoMOD, an ongoing design-build-evaluate project.
“I’m very excited about the way the current generation has recognized that design can have a positive impact on people’s lives, whether it’s through reduced environmental impact or improved housing. That’s important. What we need now is to get more sophisticated about how we go about that, not just pretend that we’re doing something great. We need to analyze the work and evaluate it to determine what impact the built results actually have. This happens in every other design industry, but the starchitect system is based upon the idea that you do the amazing project, you might even talk about some of the social and environmental attributes, and you get it published in a good magazine—but that’s it. You don’t go back to see what happens afterwards.
“To tap into the affordable-housing market, it’s important to understand how the modular industry really works and not imagine that you can completely rethink all aspects of it. If a prototype is going to cost one hundred percent more, with the promise that it will get a lot cheaper in production, that’s frankly not going to cut it when it comes to the final per-square-foot cost. The difference between on-site and off-site fabrication is maybe fifteen to twenty percent. So if your prototype costs more than twenty-five percent above what an affordable house normally would, you won’t get into that market.
“For our first three ecoMOD prototypes, we combined panelized systems with modular construction, which is almost unheard of. The reason the modular industry stays with stick-frame construction is that their crews are trained to build from the inside out. They build a wood frame, put on the Sheetrock, and then do the plumbing and electrical from the outside while they get it mudded and painted on the inside. That way they are able to move a house down the line in four or five days. It’s the interior-finish work that takes the longest on the factory line. If you are going to use panelized systems, you are messing it all up. They take some finessing from the inside and the outside, which adds time and cost. Since we’re working with Habitat and a modular builder that uses stick-frame construction on ecoMOD4, we’re going that way. But we’re going to work out an alternative version to get the insulating-performance level you can get with a panel.”
How to design sustainable, affordable manufactured housing:
1. Research. The prefab-housing world is filled with visionary but failed prototypes. Designers need to dig deeper to understand how the industry actually works and push for measured changes toward sustainable and affordable options.
2. Listen. Curb your ego, but not your ability to learn something from affordable-housing experts, builders, businesspeople, environmentalists, and potential homeowners.
3. Research some more. Calling it green doesn’t make it green. Rigorous sustainable design is tough—it requires considerable research time and should not depend on preconceived notions of what’s environmentally preferable.
4. Collaborate. Effective design requires equal parts vision and practicality. Interdisciplinary collaboration is the best way to achieve that, and I believe that group genius is more productive than individual genius.
5. Evaluate. A building is a hypothesis that needs to be tested. Designers aren’t very good about learning the lessons of their work, but that’s the only way to make sure your building is actually affordable and sustainable.
From the Notebook of Bryan Bell
