Modular Construction: Prefab Reduces Residential Footprint

The heyday of palatial suburban homesteads may be coming to an end. Pundits predict that, by 2050, today’s single family suburban residence will be home to three to four families. The average family in the future won’t have the resources on its own to afford a suburban lifestyle.

In the near term, civic administrations are increasingly concerned about how to fund suburban infrastructure development and reduce the environmental impact of urban expansion. The housing industry is caught in the middle, uncertain about how the clamour for more sustainable growth will actually play out.

While the industry dithers, consumer demand for eco-friendly homes is rising. In response, some builders are recognizing that small really is beautiful. They’re developing homes in the inner city and for recreational use outside city limits that achieve special efficiencies by using prefabricated modular elements. It’s the perfect answer for many home buyers looking to downsize.

The statistics are alarming. The typical suburban homestead is an energy guzzler and a disgrace to the environment. Just constructing it conventionally results in 10 to 12 per cent of new material going to landfill. Heating and cooling are a burden as well. In Canada, the average home creates almost 11 tonnes of carbon dioxide annually. This is equivalent in greenhouse gas emissions to running two cars or using 23 barrels of oil.

If this isn’t enough to create a stampede to more sustainable housing, the price tag for big houses and their utility bills should be a definite incentive. A new generation of home buyers is looking for smaller eco homes and lower utility bills without compromising on style or function, and some manufacturers are responding.

Based in Calgary, Karoleena Homes builds modular eco homes, including the Karoleena cabin. This 650-square-foot recreational unit is one example of the trend to prefab, energy-efficient construction. Intended as a summer home, the cabin is also a potential candidate for use as a secondary suite in municipalities where these are permitted.

Modularity, done with the environment in mind, should translate into quickly assembled yet well-built residences, without the long timelines and inconsistencies in quality sometimes associated with conventional building.

The cost per square foot in a Karoleena home compares favorably with current market rates for well-designed and constructed units. The company recommends a four-month timeframe for custom-built designs using structural insulated panel (SIP) technology, and a matter of weeks for the steel-framed Karoleena cabin. In contrast the average suburban home can take seven to nine months to deliver.

On the inside, the Karoleena cabin has a modular, movable interior wall system from DIRTT Environmental Solutions. DIRTT, also based in Calgary, is best known as a manufacturer of modular interior walls for commercial and institutional uses. The Karoleena cabin marks the first time the prefab interior system has been deployed for the wider residential market. Modular elements turn a small house into a spacious one and ensure flexibility of use. Material selection and clean assembly can dramatically reduce environmental toxins and improve indoor air quality.

DIRTT’s most recent innovation for home buyers is the embedding of elements into walls. Featured in 2011 at the company’s booth for the Greenbuild and IIDEX trade shows in Toronto, foldaway beds and desks transformed a feature wall into a bedroom or office. Adaptability of this type ensures a small home is functional in spite of its modest size.

The advantages of modular construction on the interior include speed, quality of construction, minimal waste and economies of scale. Everything, including electrical wiring and flooring, is manufactured in a controlled environment, which means materials are not exposed to the elements or degraded by light and moisture conditions. Smart software for design, specification and manufacturing enables cost-effective customization of designs and reduces the manufacturing footprint by 30 per cent.

Scaling down shouldn’t mean having to settle for less. With cities across Canada struggling to implement more sustainable urban growth policies, modular and adaptable systems may be just what the market needs. Regardless of what the economy is doing, builders and manufacturers have an opportunity with innovative, small-scale residential offerings.

Andrée Iffrig is a LEED AP and passionate advocate of sustainable design and development. A graduate architect and RAIC medalist, she works in communications for DIRTT Environmental Solutions. For more information please visit and