Prefab Housing Considered

A prefab house is one that is largely built in a shop and assembled in sections on the site. The concept has been around a long time, since a Michigan company called Alladin offered the first kit house in 1906. Sears, Roebuck & Co. started selling prefab house kits in 1908, selling nearly 100,000 by 1940. Prefab enjoyed a resurgence of popularity after World War II when hundreds of soldiers returned home to start families and needed housing that was both quick and cheap.

In recent years prefab housing has seen renewed popularity. Proponents claim that it is “greener” than stick-built housing, generating less construction waste and using fewer materials because it is built in a factory under controlled conditions. Dwell Magazine has been championing prefab design as a way for households of modest income to afford good, green modern design. Their Dec/Jan 2012 issue includes a 42 page article on the current state of prefab housing.

Summarizing the Dwell article, we realize that:

Prefab is perfect for vacation houses built on rugged and remote lots, where the expense of transporting materials, equipment and labor is a significant cost factor.

Some people opt for hybrid construction where only some of the building components, like the exterior walls, are prefabricated off-site.

One prefab house took two years to build, contrary to the common understanding that prefab is quicker than stick-built construction.

Another house ended up using insulated concrete form (ICF) panels when prefab of the exterior walls proved more expensive than building on site. Which goes to show that prefab is not always cheaper.

Some prefab companies estimate 9 months for design and 9-12 months for construction. This is about the same time required by a custom site-built house.

Prefab is a technique not a product. While it is not always the cheapest or quickest option for construction, it does have the advantage of predictability. Variables that affect on-site construction can be better controlled in a factory.

Dwell’s Shoppers Guide to Prefab Housing showcases 22 companies, each company having a slightly different way of working.  Important items which may or may not be included in the price of prefab housing are: permits, land, site plans, site preparation, utility hook-ups, foundation, transportation, cost of assembly, additional materials, and parts to be purchased by homeowner

The discussion about pros and cons of prefab housing is passionate and detailed. To expand your grasp of the issues surrounding prefab construction, check out this thoughtful and detailed evaluation from 2008 by Chad Ludeman of Postgreen Homes. Tedd Benson of Bensonwood Homes has a lengthy and articulate response to this article, and Lloyd Alter of Treehugger mentioned a few points to consider as well. Allyson Wendt of Building Green added her thoughts on the future possibilities of affordable, green prefab.

Image: prefab home by Minarc.