To make the most of my time at Greenbuild 2010, I scanned the seminars for a topic that seemed to impact the concrete industry. “Systems Thinking for Residential Buildings” promised to compare the environmental benefits of green building practices that use less material or reused materials over the lifetime of a home.
The summary caught my eye, considering concrete's best qualities—durability, energy efficiency, and design flexibility—are also green assets. The session focused on a 2010 report commissioned by the Oregon Department of Environmental Quality (DEQ), called A Life Cycle Approach to Prioritizing Methods of Preventing Waste from the Residential Construction Sector in the State of Oregon.
The study was conducted by Quantis environmental life cycle assessment consultants, the nonprofit Earth Advantage Institute, and the Oregon Home Builders Association. Its ultimate goal: to help prevent waste in residential building and maximize overall environmental benefits.
The team used life cycle analysis (LCA) to evaluate environmental benefits of methods used to reduce material use and prevent waste during the design, construction, maintenance, and demolition of residential buildings.
LCA gives an overall picture of environmental impact. The “cradle to grave” approach determines how much energy and other resources go into a product and how much waste is generated, from raw material production to manufacturing, and ultimately disposal or recycling.
One building material may seem greener than another in terms of durability. But during production, its initial environmental impact might be greater. LCA looks at the entire process for an accurate comparison.
To paraphrase the study's executive summary, the greatest environmental benefits are achieved not through managing waste during construction or renovation, but by reducing the material and energy used over the lifetime of a home. This could be a great opportunity for concrete.
A light bulb moment
While the study does not endorse any specific building material, my own conclusion was simple: Homebuilders should be using concrete products. The Oregon research showed that over a product's life cycle, manufacturing and BuildBlock Building Systems producing new materials has a much greater impact than material disposal. Building with durable materials such as concrete adds longevity to a structure and can reduce new material production in the long run.
The team identified energy use as the “dominant contributor” to a home's environmental impact. Concrete products such as insulating concrete forms (ICFs) and insulated precast panels can result in dramatic energy savings.
The research suggests reducing overall environmental impact by building smaller homes and sharing resources in multifamily developments. Coincidentally, high-efficiency concrete products are a cost-effective solution in multi-unit construction, such as dormitories.
Concrete can also reduce finishing materials. Insulation, drywall, and carpeting are some of the biggest waste producers. They need to be repaired or replaced over the lifetime of a home, and are not easily recycled. However, concrete walls and floors can double as finished surfaces.
Word is already spreading in the industry. When I spoke with BuildBlock Building Systems at World of Concrete, the ICF manufacturer shared product updates—and a summary of the Oregon DEQ report. With high energy efficiency, ICFs ranked in the top 10 in a list of 25 construction practices that provide climate change benefits. Results like this could cement concrete's green reputation.