Sustainable construction involves assessment that includes considering the environmental, economic, and social aspects of the built environment. Factors that need to be addressed are energy efficiency, material selection, construction waste reduction, indoor air quality and the general health and well being of the occupants, to name a few.

The statistics coming out of the building sector are staggering. Energy efficiency becomes an economic concern given the Rocky Mountain Institute estimate that $15 billion a year is wasted on heated and cooled air flowing out of leaky buildings. Material selection becomes an environmental concern when it is realized that the average 2000-square-foot home built in America requires approximately 1 acre of forest which equals about 44 trees. Approximately 1.5 million homes are being built a year, providing enough framing lumber to stretch to the moon and back six times. Every year 136 million tons of construction waste is sent to the landfill, almost a ton per house. The social effects of buildings arise as a health concern with the estimate that Americans spend ninety percent of their time indoors. This number, coupled with the facts from the U.S. Environmental Protection Agency: on average, indoor air is two to three times more polluted than outdoor air, which prompts an imperative to change the way we build.

Issues surrounding energy efficiency have spawned the field of building science which studies how buildings interact with the elements. Controlling moisture, air infiltration, and maintaining a continuous layer of insulation are a few of the considerations in this discipline. This field focuses on the construction of high performance buildings as well as improving existing structures. The emergence of this field has greatly improved the energy efficiency of construction by decreasing the economic burden of wasted energy we are bearing. It is also increasing the lives of our structures due to their protection from the elements.

Concerns about the sustainability of construction materials have spawned movements such as certified wood programs, advanced methods of construction, and the resurgence in natural building. Certified wood programs require wood to be harvested in a manner that keeps the forest healthy and allows for continual growth for future generations. Sustainably harvested wood is becoming more available. Ask for Forest Stewardship Council (FSC) certified wood (www.fscus.org).

Some examples of advanced construction materials include structural insulated panels (SIPs), insulated concrete forms (ICFs), and autoclaved aerated concrete. SIPs surround ridged insulation like styrofoam with oriented strand board (OSB), a composite product which resembles plywood. These units, which range from 4' X 8' to 8' X 24', are lifted by a crane, and placed on the foundation as a wall system and atop the roof as the sheathing and insulation. SIPs, if installed correctly, are extremely energy efficient and allow the project to be under roof in a fraction of the time compared to stick frame construction (www.sips.org). Insulated concrete forms are foam blocks that are stacked in a running bond which provide a permanent insulated form for concrete. Concrete is poured into these forms one floor at a time. ICF construction provides the homeowner with an airtight, solid home that is highly insulated (www.icfweb.com).

There are at least twenty other advanced construction methods on the market. Some other examples are an energy efficient log home (www.enertia.com) pre-cast concrete walls that are brought in on a crane (www.superiorwalls.com), and geodesic domes, the creation of the inventor Buckminster Fuller. Many of these methods of construction are comparably priced to stick frame construction and use less wood than conventional forms of construction while providing other benefits wood buildings cannot.

One of the most effective methods of reducing the impact structures have on our natural resources is building appropriately sized structures. Oversized residential homes are a chronic problem in the U.S. and have been termed McMansions by Sarah Susanka author of The Not So
Big House.

Natural building has seen a renaissance in the US. Some consider building with natural, minimally processed materials to be the epitome of sustainable building. Others like it because it can be owner-builder friendly. Older ways of building such as cob and adobe are being rediscovered, while cordwood and straw bale construction are reaching maturity and are being refined. Cob uses soil mixed with straw and sand to make “loaves” that are stacked for a wall. Cordwood masonry is done using firewood sized logs as bricks, with the ends facing inside. As one of the most publicized natural building methods, straw bale construction is becoming more popular by being covered on Home and Garden television and Natural Home magazine to name a few.

Waste is a big concern when it comes to construction (look at the dumpster on any construction site). One way to address construction waste is through the waste reduction requirement of the many statewide green building programs such as Earthcraft House in Georgia, Built Green in Colorado, and the newly developed NC HealthyBuilt Homes. Reducing waste lessens the impact that construction has on our landfills and our natural resources. Reduction in waste can largely be achieved by planning the use of resources and recycling or donating what cannot be utilized. Green building programs recognize this practice as a contribution towards sustainability by awarding points for recycling/donating construction materials. These points in turn assist homeowners in achieving certification under their state green building program (http://www.ncsc.
ncsu.edu/programs/NCGBPChecklist.pdf).

Americans spend ninety percent of time indoors, according to the Worldwatch Institute. Indoor air quality, access to daylight, and accessibility are just a few of the concerns. Indoor air quality is a concern given the massive amounts of chemicals used in the construction industry that can adversely affect our health. Access to daylight is often a rarity in buildings, yet is proven to dramatically increase productivity in schools and businesses. Ensuring the health and well being of all a building’s occupants is of paramount concern when implementing sustainability.

Accessibility for the physically disabled is required by law for all commercial and state buildings. However, these standards are not always extended to the residential market. Accessibility involves keeping primary rooms on the ground level, keeping doorways three feet wide or greater, having wheelchair accessible bathrooms and showers, having door pulls and handles that are easy to operate, and turnaround space for wheelchairs in all rooms. These adaptations allow a home to be accessed by the physically disabled as well as the elderly. A house designed in this way implements a practice termed universal design and is responsive to the physical demands and challenges of life.

Sustainable construction is a rapidly emerging and vast field of study. Changes in our environment caused by buildings, and the effects on our health that living in them cause have alerted us to a broad problem. We have to find a better way to build. The answer is not one building method or design. The answer is in the diversity of building methods that we currently have, sustainable assessment of each, and the ability to always make them better.

Marcus Renner is co-founder and manager of Appropriate Building Solutions, Inc., a sustainable construction company in Asheville, NC: abs@buildsustainable.com, www.buildsustainable.com or 828-350-0451.

Myrick Rozier is completing her Master's degree in Industrial Technology and Building Science at Appalachian State University in Boone, NC.

Back to New Life Journal..