Prefab Homes

One-quarter of all non-industrial waste in the United States is generated by construction and demolition. Although some waste in the construction of a home is unavoidable, it’s hard to call a home sustainable when an excessive amount of waste arises during its construction. The sustainability of any project is largely defined by how much waste is created during its construction, particularly in the construction industry because of the massive amount of resources construction consumes. For the waste-conscious home buyer looking for a green home alternative, prefab homes are a fine option.

Modular or "prefab" (short for "prefabricated") homes are mostly built in pieces or modules in a factory then shipped to the site for final assembly and construction. Modular or prefab homes are considered a green choice because they produce less waste and are built in a central location, which means less impact on the site and fewer workers burning fuel driving to and from the site every day.

Waste

Because prefab homes are built in a factory according to well-worn plans, and they thus offer a more precise estimate of just how much material is needed for construction. Returning unused materials to the factory means that leftover components can easily be reused. Prefab home projects also present less risk of building materials getting damaged or stolen, as is often the case on construction sites.

These homes do, however, require more material in their construction. To survive the drive from the factory, the framing needs more raw materials to support it during transportation. Estimates for the extra amount of raw materials required varies according to the source. Chad Ludeman of PostGreen Homes puts it at 20%–30%, while Method Homes puts it at 5%–10%. During transportation, materials can also come loose and get lost or damaged, although this is not an issue for panelized homes that have their components packed flat for delivery, writes Tedd Benson of Bensonwood Homes.

So more materials are used to produce a prefab home, but are those materials necessarily wasted? The extra materials used to support the components while in transit do provide added durability. Materials on site get wasted through theft, rust, or water damage or simply from getting tossed. So which is a bigger waste? Adding extra material that a stick-built home wouldn’t need, which makes the prefab home more durable, or the waste of theft, rust, water damage, or getting tossed? If construction materials are stolen, those materials may still be used to build, but who really knows? Construction materials that are tossed can be recycled, but the question then becomes how much of these jettisoned materials get recycled and how effective is the recycling process (i.e., how far do the recycling trucks have to travel and how much of what is “recycled” actually gets “recycled”)?

Although prefab homes need to be transported to the site, the overall amount of transportation required to build one is minimized because workers "build" the home in a central location (i.e., the manufacturing plant) rather than traveling by truck to a potentially remote site every day, which means fewer CO2 emissions. Since as much as 90% of a prefab home is built in a factory, less time is spent on site, therefore disturbing the site (and neighbors!) less.

Time

Prefab construction saves time. Because these homes are largely constructed off-site, the deconstruction of previous buildings and laying of the foundation can happen at the same time as much of the construction. This efficiency means that homes can be built in as few as three months. It would be rare to find a contractor able to put up a stick-built home in that time.

Health

Materials on construction sites are subject to rain, wind, and snow and can develop mold, mildew, and rust. When these materials are stored in the controlled indoor environment of a factory, they are exposed to far fewer adverse environmental conditions and less likely to rust or grow mold and mildew.

Cost

Some claim that prefab homes are cheaper than conventional homes and some don’t. In any event, prefab homes have a few things going for them: shorter construction times, reduced labor costs, less waste, and potential savings from volume discounts that can pass on savings to the home buyer. They are also cheaper to build in remote areas and in areas with high labor costs. However, they are subject to certain high costs, such as paying for the crane to install the home and trucks to transport the building components.

The variable price of labor has a lot to do with fluctuating home building costs. In a boom economy, labor costs go up, which means that prefab’s benefit of cheaper labor results in greater savings than in a poor economy, when contractors are willing to work for less.

Transportation costs are the major hurdle that prefab home buyers face. Due to their massive size, these homes cost a bundle to transport. Seeing this opportunity to cut costs, Connect:Homes has developed a patent-pending modular system that enables them to transport their homes by using standard-sized, Intermodal shipping containers anywhere in the world for a fraction of what it would cost to ship a standard prefab home.

With the high costs of installation, putting up a small prefab home doesn’t offer the same financial benefit as it does when scaling up, although this growing industry offers a steadily increasing range of options. LivingHomes offers a variety of models starting at $145 per sq. ft., the cheapest being their C6.3 model, a 958 sq. ft. two-bedroom that starts at $139,000.

Is the price worth it for prefab? Every home buyer has different values, and buying a sustainable home adds an extra layer of values to assess. Here's one thing any green home buyer can appreciate: the less material wasted in the construction of a home the better – which, among other things, is one major benefit prefab has going for it.