Materials Impacts

A real assessment of the environmental impacts of materials is still somewhat terra incognito in the green building movement. It is one of the most complex areas to evaluate from an impacts perspective and essentially impossible to determine "savings."

Some things can be counted, such as the volume of materials diverted from the landfill and the approximate embodied energy of materials reused. The data for LEED EBOM are still weak in this area, so we will focus our analysis on the impacts from LEED NC and LEED CS.

Building & Materials Reuse: Reusing buildings is becoming more common for LEED certified projects, with more than 12% of projects reporting major reuse of buildings and interior components. In square footage terms (based on LEED NC only), this totals 37 million square feet to date. We forecast that this figure will exceed 400 million square feet by 2020.

Materials reuse is still somewhat lagging in LEED projects as it has taken time for adequate sources of quality reused material to develop and reach the market. We evaluated the environmental impacts of materials reuse in terms of savings in embodied energy, concluding that materials reuse in LEED buildings has saved the equivalent of 70,000 barrels of oil, a number that will grow to nearly 800,000 barrels equivalent by 2020.

Construction & Demolition Waste: Aggregate data show that nearly 60% of the C&D waste generated by LEED projects is diverted. Between the Certified and "Built to LEED" projects, we estimate that LEED buildings to date have recycled or reused a cumulative total of 24 million tons of waste. These diversion figures mushroom to 200 million tons in 2015 and 325 million tons in 2020. (See Appendix for the "Built to LEED" project definition.)

Green Materials Impacts: The varied use of materials and the lack of good data make an evaluation of materials' other impacts difficult. For this reason, we will follow LEED's lead by evaluating several materials categories on a dollar basis.

Based on average materials costs, local and recycled-content building materials for LEED Certified buildings represented approximately $10.5 billion in cumulative spending through 2008. By 2020, total spending in this area is expected to grow more than tenfold to almost $110 billion. We should note that these figures are conservative because they do not include the value of materials that are evaluated based on their indoor environmental quality characteristics, such as low-VOC paints and nontoxic adhesives.

As LEED moves toward a more normalized lifecycle assessment basis for evaluating the onsite, upstream and downstream impacts of materials use in buildings, we will be better able to evaluate these impacts comprehensively.

Certified Wood: Based on average non-residential wood use estimates and the penetration of the certified wood credit in LEED, our analysis shows that to date more than 100 million board-feet equivalent of Forest Stewardship Council certified wood has been installed in LEED projects. If current penetration rates continue, this utilization will reach nearly 1.3 billion board feet by 2020.