In praise of prefab housing
Construction method offers both style and energy efficiency, author says
Sheri Koones is the author of six Prefabulous books, including Prefabulous Small Houses (Taunton Press, 2016; $21.95 US), which features 32 livable, sustainable prefabricated homes — including six from the Seattle area. Here Koones answers a few questions about the appeal, and the reality, of prefabricated homes:
Q: What kind of evolution have you seen over the years in the industry, and in homeowners’ views toward prefab?
A: The technology of building prefab has become so much more sophisticated over the years. In the early days of prefab, the designs were limited. Today, the sky is the limit on what can be built prefabricated. Unfortunately, there is still a stigma regarding prefab construction among those unfamiliar with the process. But little by little, more people are finding out about prefab and saying it’s the only way they would build. It’s hard not to be impressed by all of the gorgeous prefab houses around today. Each time I do another book on the subject, I’m blown away by the beauty and efficiency of the houses I find.
Q: What are some specific benefits of modular construction?
A: Building prefab saves a good deal of time over building on-site. Since the components are built in a factory, they aren’t exposed to the elements and compromised by changes in weather and snow/rain. Prefabs are built by professionals in factories, where they continuously build houses and are extremely proficient at their work. Cutoffs from wood are saved for other projects, and metal and drywall are recycled. There is far less waste in the factory and less pilferage on site. There is less damage to the property with prefabs that are transported and set — less cutting down of trees and piles of debris. Neighbours appreciate the lack of construction noise and the lack of trucks coming in and out of the site when a house is built prefabricated.
Q: How do the costs of a prefab home compare with those of a traditional home?
A: This is a question I often get and one that is difficult to answer. The difference in cost really depends on the area of the country — where labour is very inexpensive, the difference may be slight. In metropolitan areas where labour is more costly, the difference may be significant. In a study by Going Mod (prepared by the Building Industry Association of Philadelphia and FixItPhilly), they found modular construction saved $32 US per square foot over site-built construction. I understand cost is a major issue when building a house, but the other advantages that come with building prefab need to be considered as well.
Q: You write that building better is preferable to building bigger — can you give examples of recent innovations, products or materials that contribute to better, smaller homes?
A: What I mean is that it’s better to put more money into using the best materials and systems in the home, rather than building the house bigger: • Building a highly efficient envelope is the single most important element in building better. This includes a well-insulated foundation, high-efficiency windows (triple-paned ones are available today), the correct size and placement of windows, excellent insulation and a high-efficiency roof. A blower door test performed before the house is complete will show if there is any air infiltrating, which can then be corrected. • There are more highly efficient appliances now available than in the past that are Energy Star rated and use far less energy. • Heating systems include radiant floor heating and cooling and heat pumps. Heat recovery ventilators (HRVs) are now being used in the tightest and most efficient homes to keep the interior air fresh. The warmed or cooled interior air is exchanged with the fresher outside air without losing the heat or “cool.” • Tankless water heaters may cost a bit more but save on electricity in the long run. Drain-water heat recovery systems capture the energy from grey water and use it to supplement the water heater. Dual-flush toilets and grey water systems conserve water. • LED lighting has become the norm, saving energy and the need to continuously change bulbs. • Solar hot water and photovoltaic panels save energy. I predict solar roof shingles will become popular for environmentally conscious homeowners in the future. Solar City projects they will be available to the public sometime after summer 2017. These PV solar shingles should be easier to install than PV panels and will be more attractive.
All of the homeowners I interviewed for this book were totally happy living small or smaller than their previous houses. They find them cosier, needing less maintenance and a better way of life.
Q: Clearly, judging by your books, “prefab” does not equal “boxy and boring.” Are there any other prefab myths you’d like to put to rest?
A: There is also the belief that prefab homes are poorly built. But again, that is a total myth. Building houses in a protected environment by professionals, whose work is checked and checked again, creates a better-built house.
Just as none of us would like the parts of our car dropped off and put together by a local contractor, many homeowners today can appreciate the precision and professionalism of houses built in a factory.