The Green Prefab myth?

It seems like every day I read another article about the newest, greenest, most sustainable prefab home. My next few posts will take on the idea of prefab - looking at some notable examples, but first, here are some of the ideas behind this trend.

What is Prefab?

Prefab, short for prefabrication, refers to a construction technique where parts of the building are manufactured and assembled in a facility before they are transported to the building site. Although the term is used quite commonly today, especially in reference to sustainable building and green design trends, it incorporates a number of different techniques and practices. Perhaps the most important common aspect of these practices is that they differ from conventional home construction [i.e. bringing materials to site and constructing the building there.] Although often times, "prefab" also refers to the style of appearance of the house, implying a "modernist" appearance or aesthetic.

Why is Prefab [assumed to be] sustainable?

The idea behind prefab construction is the logic of the assembly line -- the assumption that mass-producing building components in a factory will save time and money. Fewer skilled workers are needed onsite and prefab buildings can be built much more quickly than those that are conventionally produced, allowing for an earlier financial return and minimizing the time potentially spent in bad weather/hazardous conditions at the building site.

Other benefits include the following: the quality control of building components can [theoretically] be maintained at a higher standard, skilled labor can be localized in one place and exported elsewhere, and manufacturing can be centralized where the cost of labor, materials, and energy are cheapest. Additionally, the production of standardized parts means less waste, which is also intended to cut costs.

So, as the theory of mass production goes, prefab equals cheaper.

Does Prefab mean Green?

Yes, and no.

There are a number of examples of prefab homes which, I would argue, are pretty green. However, I would be weary of claims such as those made on prefabs.com: "Prefab = Green! Building a prefab home is earth friendly. Prefabrication techniques reduce waste, offer energy-saving designs and improve manufacturing and construction efficiencies."

First of all, the energy saved in the manufacturing process must be weighed against that used in transporting the prefab components to the site, which, depending on the size and the location, can be incredibly expensive and energy intensive. Second, the logic of prefab construction relies on an assumption that there is an optimal building system, configuration, and fabrication technique that does not depend on local knowledge, vernacular building practices, site specific constraints, individual desires, or personalized craftsmanship.

There is certainly an argument to be made that more efficient means more sustainable, but there is also a counter argument against this one-size-fits-all mentality -- that green design should reflect the vernacular traditions of a particular place, account for specific site constraints and atypical conditions, and result in buildings that are embedded within a local economic structure.

Next time:

A survey of some green prefab homes.