What’s “rapidly renewable”?

Rapidly renewable materials must have a harvest cycle of 10 years or fewer. This includes materials like bamboo, agrifibers, and others listed on the chart below. Materials for this credit can come from either plants or animals—but they have to be harvested without harming the animal. Wool is okay; leather isn’t. 

“Big ticket” items are just the ticket

This credit can be very easy to achieve—it only requires that a small percentage of the materials budget be spent on rapidly renewable materials. But it can become challenging unless you make a concerted effort to research and specify products with rapidly renewable content in mind. Don’t wait until materials are purchased to calculate your credit compliance—chances are, you won’t make it.

Focusing on a few more expensive items with rapidly renewable content can be an easy way to make sure that you meet the budget threshold while minimizing the number of products you will need to track and document.

Finish materials tell a “green story”

Rapidly renewable materials can be an effective advertisement of your project’s commitment to “green”—many rapidly renewable materials make great interior finishes, including bamboo flooring and veneers, cork flooring, wool carpeting, agrifiber casework, and others. Projects interested in “telling the green story” through their choice of finish materials will often pursue these materials.

There are affordable options

While finish materials may come at a cost premium, there are plenty of other ways to use rapidly renewable materials less visibly and more affordably: strawbale construction, cotton batt insulation, cork carpet underlayment, and agrifiber boardA composite panel product derived from recovered agricultural waste fiber from sources including, but not limited to, cereal straw, sugarcane bagasse, sunflower husk, walnut shells, coconut husks, and agricultural prunings. The raw fibers are processed and mixed with resins to produce panel products with characteristics similar to those derived from wood fiber. in millwork, to name a few. (See table above.)

Knauf’s EcoBatt fiberglass insulation uses the company’s Ecose binder, which is manufactured using rapidly renewable materials instead of petroleum derivatives. Photo – Knauf Insulation

Suit the materials to the space

It’s also important to select rapidly renewable materials that best suit the function of the space. For example, cork absorbs sound well, which would be useful in a classroom setting. On the other hand, there may be situations when it might be better to choose a recycled material instead—wool carpet in a high-traffic area, for example, would not be as durable as recycled-content commercial carpet and would wear out more quickly. 

Double dip with MR credits

Products with multiple environmental attributes—such as rapidly renewable and regionally produced—can contribute to multiple LEED credits.

FAQs for MRc6

How does this credit treat materials that come from animals such as wool or leather?

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. See LEED InterpretationLEED Interpretations are official answers to technical inquiries about implementing LEED on a project. They help people understand how their projects can meet LEED requirements and provide clarity on existing options. LEED Interpretations are to be used by any project certifying under an applicable rating system. All project teams are required to adhere to all LEED Interpretations posted before their registration date. This also applies to other addenda. Adherence to rulings posted after a project registers is optional, but strongly encouraged. LEED Interpretations are published in a searchable database at usgbc.org. #2549 for details.

What building components are typically purchased with renewable materials to reach the 2.5% credit threshold?

Big-ticket items commonly used for this credit include flooring, insulation, millwork, wall coverings, and coatings. These products can have enough combined cost to reach the credit threshold, and renewable options are generally widely available. That said, there are many other products made with renewable materials that can contribute to this credit, so taking the time to explore the opportunities specific to your project can be worthwhile.

A manufacturer is claiming that certain trees, e.g. balsa, acacia, mesquite, can be harvested within 10 years, and thus contribute to this credit. Is this acceptable?

Yes. There is no official list of acceptable plants, but any biobasedGenerally, classification of products and materials derived from plant and animal sources as opposed to minerals. The U.S. Department of Agriculture has a program to promote the use of emerging biobased products that defines them more narrowly, to exclude products that already have established markets, such as food, animal feed, and lumber. material that otherwise meets the requirements should be accepted, if you can get formal documentation from your supplier that the life cycle is less than 10 years.

Be careful, though—the caveat that USGBC provides in LEED Interpretation #10057, dated 5/9/2011, is that the plants must be "typically regenerated" within 10 years. Trees that could economically be harvested within 10 years, but for which that practice isn't typical, might not meet this standard.