With regard to resource efficiency, we need products that consume fewer high-value natural resources both initially in their manufacture and over the long term. So, we really like products made from rapidly renewable resources, salvage, recycled or waste materials, or that have been otherwise repurposed from existing, not virgin, resources. Or products that serve more than one purpose, like concrete foundations as finished floors, so additional flooring products are not required. And products that are reusable or recyclable at the end of their lives, saving further depletion of our natural resources in the future.
- Salvaged Materials:
Materials that have been reused from deconstruction or demolition projects can find new life cycles as either the same application as before or in a completely different application. Wood flooring is the most commonly salvaged and reused building material. Another is brick masonry, which is often reused as hard surface paver materials (e.g., for driveways and walkways).
We have also seen many affordable projects constructed or remodeled with numerous salvaged materials, including cabinetry, doors, bathtubs and sinks and even scrap lumber used as paneling. Sources include resale shops, like those run by Habitat for Humanity to raise funds for their own construction of affordable housing units, as well as similar facilities run on inventories created by demolition and deconstruction companies. There are even extreme homes constructed entirely with salvaged materials, such as Earthships, which use old tires filled with dirt and plastered into retaining walls using adobe or cement to form the building shell. In some areas of the country, lacking any facilities within a reasonable distance that might be able to recycle these tires, they could have easily ended up in a landfill. We have also read of and seen photos of structures built entirely from glass bottles and mortar. Are these homes green? From a resource efficiency standpoint, yes.
If you think about it, before mankind had the ability to ship various materials across the country or around the world, all homes were built out of local available materials, whether they were virgin resources or reused existing components. In fact, in those days, there were no such thing as landfills and new resources were scarce, so things were used as long as they were useful. Are we resurrecting this into a new trend?
- Materials That Have Recycled Content or Waste Content:
Sometimes it is difficult to estimate all the energy required to salvage, transport and repurpose materials into new products as compared to that used to harvest raw resources in order to determine which is greener. We have already discussed the impact on the environment from many of the practices used to extract virgin resources. We also know that when natural resources become depleted, their cost increases, affecting the affordability of the material and thereby impacting the overall cost of housing. So, in the end, recycling wins.
- Basically, there are two types of recycled content for manufactured goods:
Post-industrial (waste products from the manufacture of another product) or post-consumer (waste product of a product already used). An example of post-industrial waste would be oriented-strand board (OSB), made from wood chip waste created in the milling process of other wood products. An example of post-consumer waste would be those flimsy plastic grocery bags that can be recycled into carpet and composite decking materials for patios. Post-consumer waste is the target, as most of that ends up in landfills, so recycling it not only saves virgin resources but also reduces the landfill mass that contributes to greenhouse gas emissions.
There are many other products on the market that contain recycled waste materials, everything from recycled glass or paper countertops to recycled rubber tires made into a mulch product. Building products to look for with recycled content include metal roofing, roofing asphalt shingles, sheathing and house wraps, window frames, roofing materials, composite decking and ceramic flooring. Insulation products are available that are made from recycled materials (cellulose is recycled newspaper, cotton is from recycled blue jeans, and, of course, recycled fiberglass). As was mentioned earlier, many products can be recycled back into production of the same product again.
- Rapidly Renewable Materials:
Sustainably sourced fast-growing species of bamboo and cork are popular choices for many durable building materials. They should be considered as alternatives to old-growth, more vulnerable wood products. Growing them does not require chemical fertilizers and pesticide treatments nor do the products made from them need periodic maintenance, such as painting, staining or sealing. These materials are commonly used to make cabinetry, flooring, countertops, insulation and trim. Look for products from certified sources that use formaldehyde-free binders.
- Bio-based Materials:
Bio-based products are generally from rapidly renewable resources, and many represent waste streams from other industries (food or fiber crops). These materials have very low embodied energy, since the energy to grow them is attributed to the primary crop. Therefore, it is only the processing and transportation energies that add measurable value to any product made from them. From corn starch to soy beans, wheat-straw shafts to sunflower stalks and rice hulls, these materials are finding their way into many building products. Look for bio-based solutions in wallboards, drywall, ceiling tiles, foam insulation, cabinetry, adhesives and caulks, as well as those used as binders in the production of other building materials to replace toxic chemicals.
- Indigenous Materials:
Raw materials sourced or products manufactured within 500 miles of the project site are considered green because they have lower embodied energies from transportation. Look for materials harvested or mined close to your area, including wood products and aggregates, and check for local manufacturers in your region. It also generally uses less energy to ship raw materials some distance to a local factory than to ship finished goods over great distances. Many national manufacturers have production plants in various locations across the country and would be happy to ship from the closest location to your project if requested.
- Products That Require Minimal Finishing:
More and more manufacturers are developing a competitive edge through product improvements that offer more durability and less maintenance. Fiber-cement siding materials are now offered with integral color finishes providing up to 50-year warranties on products that are guaranteed not to need painting for 15 years. The same is true for American clay plaster materials, available in almost as many color palettes as interior paint products. For your patio, composite decking materials come prefinished, never requiring resealing or restaining, unlike their wood counterparts.
Remember to think about how often any finish material (exterior or interior) will need maintenance or repair. Choosing products that have less frequent cycles saves money and resources over the long run.
