The living roof — also called a “green roof” —on our Welcoming Center is a 3,000 square foot vegetated surface over a membrane roof, planted with nine distinct species of grasses and succulents and irrigated with spring water that flows through the site naturally year round. We originally did not want to irrigate the roof, but found that we were required to do so for fire code reasons. On our roof you will find:

  • Festuca idahoensis—Idahoe fescue
  • Nassella polera—Purple needlegrass
  • Nassella lepida—Foothill needlegras
  • Sisyrinchium bellum—Blue-eyed grass
  • Archilllea millefolium—White Yarrow
  • Sedum album—White Stonecrop
  • Sedum lineare—Needle Stonecrop
  • Sempervivum calcareum—Houseleek Species
  • Sempervivum cantabricum—Houseleek Species

The main function of the living roof is to reclaim the land taken by the building’s footprint, allowing the myriad of local insect and bird species to continue to use the land. In addition, this allows rainwater that would otherwise run off to be captured and a portion of it to be returned to the atmosphere via evapo-transpiration. The plants on the roof also help reoxygenate the air and process airborne toxins, a feature that has less importance in our rural setting than in a city, but is beneficial nonetheless. 

Our green roof also provides us with actual, practical benefits as well. This type of roof increases the thermal mass of the building and has very good insulating benefits. At the same time, the green roof helps keep the building much cooler in the summer than the typical black tar roof. A black tar roof, which readily absorbs sunlight, can get as hot as 185ºF in the sun, while a living roof will stay below 100ºF. This, along with various other features present in the building, means that we do not have to have an air conditioning system in the building. Of course, there is also the benefit that having a living roof means there is no need to use black tar, which is primarily made from coal or petroleum and is considered toxic and carcinogenic.

Local & Regional Resources

Local or Regional Resources can be defined in a number of different ways, depending on what you think “local” means. For LEED Certification, “local” is defined as within a 500-mile radius of the site. It applies to both the extraction of a resource and the manufacturing of a product.

24% of the total value of the building materials in our Welcoming Center were extracted and/or manufactured within 500 miles of the site, with many materials originating much closer. In addition to supporting local business and feeding money into the regional economy, which are both desirable, using local materials reduces the amount of fossil fuels needed for transport, thereby decreasing our dependence on a non-renewable resource and lowering our carbon output.

Below is a list of the local and regional materials found in the building.

  • Roadbase — 17 mi.
  • Decomposed Granite — 19 mi.
  • Descobond — 41 mi.
  • Sand — 7 mi.
  • Pipe — 95 mi.
  • Straw Bale — 116 mi.
  • Coiling Grill — 407 mi.
  • Storefront Glass — 350 mi.
  • Skylights — 20 mi.
  • Concrete, sand, & lime — 11 mi.
  • Plaster, cement — 339 mi.
  • Plaster, sand — 121 mi.
  • Plaster, lime — 395 mi.
  • Finish Plaster — 395 mi.

Rapidly Renewable Resources

Rapidly renewable resources are materials that are made from plants that are typically harvested within a ten-year or shorter cycle. This type of resource regenerates itself faster than the demand for the product. Wherever
possible, we used this type of resource instead of non-renewable resources such as fossil fuel-based plastics or slowly regenerating resources like old growth wood.

Here is a rundown of rapidly renewable materials found in our Welcoming Center and their applications:

  • Straw Bale: Over 1000 bales of rice straw were used in the construction of the outer walls of the Center. Visit our Straw Bale Page for a more in-depth discussion of the straw bale construction.
  • Meadowboard: These flat, 4-by-8 foot plywood-like panels make up the ceiling in our lobby and bookstore. The boards are made from the rye-grass stems that remain after seed harvest, providing a rapidly renewable alternative to wood. In fact, these boards have strength, insulation, acoustic, and fire rating values that are superior to the properties of many wood products! Meadowboard is also naturally visually appealing; so there’s no need for a covering of paint, wallpaper, or veneer, avoiding possibly toxic or carcinogenic substances.
  • Sunflower Seed Board: Another plywood-type material, these boards contain 100% sunflower hulls and comprise many countertops, cabinet faces, and signs found throughout the building, including restroom and room name signs. Much like Meadowboard, this a beautiful, visually textured alternative to wood products. Because the material is not waterproof (again, like plywood) the counters are topped with metal or glass in the food service areas.
  • Wheat Board Cabinetry: The third plywood-type board found in our building, wheat board was used for shelving and cabinetry throughout the building. Like the last two, it provides a rapidly renewable, attractive alternative to wood products.

Recycled Building Materials

Two types of recycled content are found in the materials used in our Welcoming Center:

  • Post-consumer—Material that comes from a material or finished product that has served its intended use and has completed its life as a consumer item
  • Post-industrial—Material generated in manufacturing and converting processes, such as manufacturing scrap and trimmings/cuttings. In both cases, recycling the content extends the life of the material and diverts it from landfill

By using recycled content, we also avoid the need for fresh resources. In the end, 13.1% of the materials found in the Welcoming Center came from recycled content.

Here is a rundown of materials with recycled content found throughout our Welcoming Center:

Post-Consumer Plastic Countertop (100%): The countertops in the bathrooms and in the employee break room are made from recycled plastic containers such as milk cartons, but contain many other types of plastics as well. Because it contains a mix of plastics, there was no need to go through the lengthy separation process usually required to recycle plastics. This process also creates a unique visual texture in which you can sometimes actually read the original cartons.

Ceramic Tile (55%): This tile is found on the floors and the walls of our bathrooms and kitchen, and it contains recycled glass.

Cellulose Insulation (70%): The ceilings in the building that are not made from Meadowboard are made from recycled newspapers and cardboard that were liquefied and blown in. In many cases, this would simply serve as insulation and would then be covered in some manner. However, we chose not to “finish” the ceiling, leaving the recycled cellulose insulation in full view. The architect chose to do this for aesthetic reasons and to showcase the insulation alternative, but it has the practical benefit of being a good sound absorber, which helps the acoustics of the building.

Post-Industrial

Cement Flooring (30%): The floors in the Welcoming Center are a 70% Portland Cement 30% fly ash mix. Fly ash is one of several Coal Combustion Products (or CCPs); it is an inorganic, noncombustible by-product of coal-burning power plants. While coal power plants are an industry that we should move away from for a variety of reasons, this nevertheless diverts waste material from landfill, where it can pollute groundwater with heavy metals. In addition, cement production puts massive amounts of carbon dioxide into the atmosphere (about a ton of CO2 for every ton of cement produced), with the total industry constituting about 6-8% of global human-generated carbon emissions. The production process is also quite energy-intensive. So, for every ton of fly ash used to replace cement, enough energy is saved to provide electricity to an average American home for 24 days. The landfill space conserved equals 455 days of solid waste produced by the average American. The reduction in CO2 emissions equals 2 months of emissions from an automobile. For more information about this subject, see Making Better Concrete by Bruce King, P.E. The cement floors of our building also provide excellent thermal mass, an integral part of the passive solar design of the building that is discussed here.

Cotton Fiber Insulation (85%): The interior walls of the building are insulated with cotton fiber insulation that came from 85% recycled blue jean material. Because this is post-industrial, this material was waste product from the blue jean manufacturing industry, as opposed to jeans that have been worn by consumers. This insulation is an alternative for fiberglass insulation, which carries various health risks (particularly during installation and removal), is a possible carcinogen, and typically uses formaldehyde-based binders. In addition, the 15% of the insulation that does not come from recycled material is nonetheless cotton and is considered a rapidly renewable resource.

Metal Roof, Doors, and Rebar (~65%): About sixty-five percent of the metal used throughout the building came from post-industrial recycled content. These materials are also recyclable at the end of their useful lives.

Fiberboard (100%): Sierra Pine Medite II medium density fiberboard panels were used for the bookcases in the gift shop. These panels are one hundred percent post-industrial recycled wood fiber and are also EPP (1) and SCS (2) certified for no-added formaldehyde.

  1. Environmentally Preferable Product, awarded by the Composite Panel Association
  2. Scientific Certification Systems

Straw Bale Construction

We used over 1000 straw bales for the exterior walls of our Welcoming Center. They are exactly the same type of bales that you would see around Halloween—they measure 25” x 15” x 48”. The straw bales at Presentation Center were installed by two Tibetan men—a Buddhist monk and a layman—who spoke no English and lived in a trailer by the pond for 3 to 4 months in late 2004. They placed the straw bales by hand, cutting and shaping them with machete-like tools and filling in the gaps with loose straw, creating thick, highly compacted walls of straw.

Why straw?

Straw is both a rapidly renewable resource and an abundant agricultural waste product. It requires little energy to bale and transfer for construction, and in many cases would simply be discarded if an appropriate use for it was not found. Our straw originated from Davis, CA, which is only about 120 miles away, making it a local resource as well.

From a practical standpoint, the straw bale walls, when finished with plaster, provide excellent thermal mass. Thermal mass is a part of the over all passive solar design of the building and is discussed in more detail there. Straw bale is also an excellent insulator, with an insulation rating of R-30. This in turn eliminates the need for fiberglass insulation, which among other things has formaldehyde in it, and the need for plywood in the walls, which can contain nasty glues that outgas over time.

A final benefit of straw bale construction is that it provides outstanding fire and seismic protection! It does not seem to make sense that building with straw bale would increase the fire safety of a building, as straw is so obviously flammable. However, fire needs ample temperature, fuel and oxygen. By compressing the straw into bales, the amount of oxygen is greatly reduced. After the surface of a straw bale or bale wall has been charred, the worse it can generally do is smolder, making it actually significantly safer than a typical wood stud with air space construction. Also, adding plaster to the outside, which is itself fire resistant, only increases the fire safety of straw bale construction. As for seismic protection, the straw bale walls have impressive ductile and compressive structural strength, which dampens the shock waves experienced during an earthquake.