Sustainable living emphasizes the three Rs: Reduce, Reuse, and Recycle. These principles can also be applied when choosing construction materials. Use of energy for the harvesting, manufacturing, transportation and wholesaling/retailing (called Embodied Energy) of "new" materials requires burning some sort of fuel, unless that energy is generated sustainably. It is this burning of fossil fuels that pollutes the atmosphere with Co2 and other greenhouse gases. Therefore, using less energy equals greater sustainability. Our goal when building an SSH is to locate materials that have the least amount of embodied energy. To do this, we begin by harvesting as many building materials from the site as possible. These materials only require energy for collection. Use of these materials reduces (the 1st "R") our need to purchase other manufactured, retailed and transported materials. Next, we look to second-use and reclaimed building materials (the 2nd "R"). For example, roughly 95 percent of the wood used in this SSH came from sustainable sources, including wood from a local 100 year old grainery that was being dismantled. No more than 5 percent of the wood used was purchased through a retail outlet. Finally, we use any recycled materials (the 3rd "R") available that will suit our construction needs. There were also times, however, when we were forced to purchase "new" materials. When doing this, we look for materials that have a high content of recycled materials.
We did also use some materials, such as concrete, rigid insulation and metal roofing, which have relatively high embodied energy. There are a number of reason for this. First of all, they each serve their primary purpose better than any other material we could afford. Secondly, they all have a very long product life-cycle, increasing their sustainability (they will not soon have to be replaced). Next, they are all DIY friendly and are easy to work with, which saves money on construction as well. Lastly, when using these sorts of materials we made sure that they each served multiple purposes whenever possible. For example, concrete not only provides great strength and durability for foundations, walls and floors, but it also provides superior thermal mass properties. Likewise, the metal roof provides weather protection, while also providing for rainwater collection, solar panel installation and fire protection.
Natural materials harvested from the site include:
Mud from the site used for adobe block making, and for earthen plaster and floors.
Ponderosa pine harvested and milled on-site used for building, including: smaller diameter beams, 2x wood for framing and cabinet making, and 1x wood used for decking, paneling and flooring.
Rock from the site used for retaining walls.
Reclaimed and second-use building materials include:
Reclaimed 2x4s, 2x8s, roof sheeting and ceiling decking from the local grainery.
8x8, 6x10, 4x6 and 2x12 large dimensional lumber milled from local wind-fallen Doug-fir.
Locally harvested dead standing Lodge-pole pine log viga beams.
Reclaimed bricks from the grainery for flooring.
Other reclaimed and second-use materials used in this home include: tile, some doors and windows, batch water-heater glass and water tanks, hardware, tools and other building materials purchased from Craigslist.com, Habitat For Humanity and other second-use building materials outlets.
Finally, we use recycled materials whenever possible. In this SSH we literally used thousands of aluminum cans and plastic/glass bottles for building non-load bearing walls. Here, the can or bottle is used to form concrete, producing strong thermal mass walls that use about half as much concrete as a poured concrete wall would use. Not only do recycled materials have basically zero embodied energy, but they are also easy to use and allow a wall to be built in any shape desired. Furthermore, by keeping these bottles and cans out of the local landfilll we are eliminating the energy it would have taken to collect them, and the mess they would have caused in the landfill. Also, by keeping these bottles and cans out of recycling centers we eliminate the huge amount of energy that it would have taken to recycle these materials. Now that's a win-win-win.