One of the key features of the LEED rating systems is that, after satisfying minimum program requirements and prerequisites, project teams may select from the available compilation of LEED credits. Those options are key not only because there is no one homogenous building type but also because owners may have sustainable features they wish pursued.

But surprising to some, there is one LEED credit that stands out, by far, as the least earned.

Accepting that LEED is no longer only new construction, and in an effort to compare apples with apples, this analysis looked at the LEED New Construction v2009 rating system.

To provide some context, credit NC v2009 EA c1 Optimize Energy Performance was the most often achieved credit, over 97% of the time, that is, on 3,927 of the 4,039 projects certified under this rating system. And such may not be surprising given the weight that LEED places on reducing energy use.

But, NC-2009 MR c6 Rapidly Renewable Materials was earned in just 2% of certified projects. It was achieved only 87 times in the 4,039 projects.

Again for more context, no other credit has achieved only in double digits. That is the next nearest credit was achieved more than a hundred times.

So, what does NC-2009 MR c6 Rapidly Renewable Materials require,

“Use rapidly renewable building materials and products for 2.5% of the total value of all building materials and products used in the project, based on cost. Rapidly renewable building materials and products are made from agricultural products that are typically harvested within a 10-year or shorter cycle.”

The intent of the credit is noble,

“To reduce the use and depletion of finite raw materials and long-cycle renewable materials by replacing them with rapidly renewable materials.”

But even to the casual observer there is a disconnect between that idealistic goal and actual buildings because it is the rare building that contains any meaningful quantity of cotton, wool, wheatboard, strawboard, cork, corn, rubber or agrifiber.

There is no USGBC list of acceptable agricultural products, but be aware there is a USGBC issued LEED Interpretation #10057 that provides the plants must be “typically regenerated” within 10 years. The Interpretation is a bit cryptic, but farmed trees can be harvested within 10 years, however because harvesting trees in 10 years isn’t typical, that lumber might not meet this standard.

Also, LEED Interpretation #2549 says that to count as rapidly renewable for the purposes of this credit, the material must be harvested without causing the animal harm, and the animal must be able to continue to regenerate the material. A good example is wool from a sheep.

Despite that the credit is almost never achieved, some have suggested it is important because materials credits play an ever increasing and controversial role in LEED v4. Not that this v2009 credit is a prequel to a v4 credit (it is not), but rather that USGBC staff weighs the pros and cons of rapidly renewable materials differently than the marketplace. For example, it has been suggested using corn as a plastic substitute in building is similar to the using corn in ethanol versus as food.

These credits for materials are complex, from transparency to life cycle analysis, as is now apparent in the reworking of the v4 materials credits. And maybe it is not so bad that corn has not become a significant building material (the role of corn in fuel is uncertain as EPA acknowledged last week that the statutory ethanol mandate can not be met)?

You can register LEED 2009 projects through October 31, 2016 and pursue MRc6 for years thereafter bettering the 2% statistic. But in lieu of corn, consider wool carpeting and agrifiber products like particle board and plywood (.. yes they qualify).