Modular homes. Manufactured homes. Prefab homes. Those words have many connotations, but “prefab homes” covers the broadest range of houses that are built — at least partially — somewhere other than the house’s actual site. Just about any construction style can fall into the prefab category, including timber-frame and log-home construction. Structural insulated panels (SIPs) can be incorporated into many prefab building styles.
Certain aspects of prefab houses make them environmentally friendly: With proper planning, fewer materials are wasted by manufacturing many similar houses in one factory, and leftover pieces are more likely to be used instead of going to landfills. Shipping modules to the building site uses significant amounts of energy, but if the materials are not partially assembled prior to arriving at the building site, they need to be shipped to the site, too (unless wood, rock or earth from local sources are available).
Prefab includes kits for do-it-yourselfers, but frequently contractors complete a prefab house on the building site. So if you find a style you like, you can hire someone to complete the project for you.
Two popular types of prefab homes are modular homes and panelized (panel) homes. Both of these methods produce traditional styles of houses. Finish work (usually including drywall and trim) is completed after the main structure is assembled and passes inspection. In most places, prefab houses must be approved by a local building inspector while the plumbing and wiring is still visible in the walls and after the house is finished.
Modular Homes
Putting together a modular home is a bit like stacking toy building blocks — but more complicated. Depending on the design of the home and the distance from the manufacturer to the building site, each “block” may be an entire house, a room, groups of rooms or only a portion of a room.
MiniHome offers several models of green modular houses. These units include solar panels, and the company avoids using toxic chemicals in any of the construction materials. No part of the house is vinyl, which can produce gasses that may cause health problems. And the only material that has formaldehyde in it is the insulation in the SIPs, which is sealed from interior spaces, so off-gassing should not be a concern.
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PHOTO COURTESY SUSTAIN DESIGN STUDIO
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| MiniHome 12X34 |
You can find more options for modular homes from the Modular Building Systems Association and on these sites:
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PHOTO COURTESY HAVEN CUSTOM HOMES
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| Modular homes often look like traditionally built homes. |
Panelized Homes
Both interior and exterior walls of panelized homes are built in sections (panels) prior to delivery to the home site. Sometimes, siding has already been added at the manufacturing plant, but usually it’s installed after the shell of the house is assembled.
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PHOTO COURTESY CONNOR HOMES
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| Wall panels are assembled indoors. |
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PHOTO COURTESY CONNOR HOMES
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| A crew sets the panels in place at the building site. |
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PHOTO COURTESY CONNOR HOMES
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| A completed panelized house looks like it was completely built onsite. |
To find manufacturers of panelized homes, check out the Panelized Home Directory from the National Association of Home Builders or these sites:
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PHOTO COURTESY JOEL KOYAMA/FLATPAK
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FlatPak houses have a more contemporary style. |
More Options
“Concrete” may not be the first building material that comes to mind when you think of prefab houses, but sections of walls made of insulated concrete can be cast prior to delivery for quicker assembly at the building site. Take a look at the Solarcrete and Standard Precast Walls sites for more information.
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PHOTO COURTESY TRI-STATE SOLARCRETE
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| This custom-built concrete home was created using pre-cast panels. |
Steel prefab houses, such as those available through KML Building Solutions, include steel panels and roof trusses.
For a more ideas on prefab homes, check out the Prefabs.com directory and read Prefabrication’s Green Promise. If you’re considering building your own home, read You Can Build a House and Kit Homes.
Do you live in a prefab home? Share your experiences in the comments section below.
