Some products help us use other products or materials more efficiently. For example, drywall clips allow the elimination of corner studs, engineered stair stringers reduce lumber waste, and concrete pigments and polishing systems can turn concrete slabs into attractive finished floors. We also recognize some products, like vacuum plumbing systems, which use less material than their conventional counterparts. Many products with this attribute are fairly unique, so we bring a skeptical eye to manufacturer claims, but not a specific standard.
Third-party forest certification based on standards developed by the Forest Stewardship Council (FSC) is the best way to ensure that wood products come from well-managed forests. Wood products must go through a chain-of-custody certification process to carry an FSC stamp.
Manufactured wood products can meet the FSC certification requirements with less than 100% certified wood content through percentage-based claims (30% certified content is required if only virgin wood fiber is used; certified-wood content as low as 17.5% is allowable if the rest of the fiber content is from recycled sources).
With a few special-case exceptions, FSC-based certification is a requirement for GreenSpec inclusion of any nonsalvaged solid-wood product and most other wood products. A few manufactured wood products, including engineered lumber and particleboard/MDF, can be included if they have other environmental advantages--such as absence of formaldehyde binders. Engineered wood products in GreenSpec do not qualify by virtue of their resource efficiency benefits alone (for more on this, see EBN, Vol. 8, No. 11).
These products are environmentally attractive because they need to be replaced less frequently or their maintenance has very low impact, both of which can reduce costs as well as environmental impact.
Robust answers on typical service life of products can be hard to come by, however. In GreenSpec we reserve this criterion for products where the material is clearly more durable than alternatives, such as an exceptionally traffic-resistant polyurethane floor finish. We refer to standardized tests for durability when they are available and appropriate.
We also consider “appropriate durability”: long life is more important in a building envelope than in interior finish materials that will be replaced for aesthetic reasons. Here, reduced maintenance can be particularly important. An example is resilient flooring that doesn’t require regular waxing: an unnecessary use of resources and a health hazard.
Before specifying efficient heating and cooling equipment, it’s important to do what we can to reduce heating and cooling loads. Insulation is one of the key products to consider here, but because there are so many insulation products on the market, we look for additional benefits. Examples include cellulose insulation with recycled content, mineral wool insulation with no flame retardants, and fiberglass insulation with no formaldehyde binders. Other products in this area are high-performance windows and glazings, products that contribute to building airtight envelopes, products that reduce thermal bridging, and window-retrofit products.
With products in this area under constant development, we are always refining our approach. For example, as we have learned about insulation products with hazardous flame retardants and blowing agents that have high global warming potential, we have removed those products from GreenSpec, pending manufacturing changes. We encourage building professionals to pressure manufacturers for those changes through specification language and purchasing decisions.
Open Joist Triforce is a open-web, parallel-chord truss with solid-wood diagonal struts. It is most commonly used as for joists, but can also be used as rafters to achieve superinsulated roofs. The solid-wood 2x2 diagonal struts are attached with finger-jointed, glued grooves, potentially increasing durability when contrasted with OSB or metal plates that could degrade or corrode over time. Each Open Joist Triforce joist includes a 34-1/8" OSB panel at one end that allows the length to be easily modified, thus allowing more economical, standard-dimension manufacturing. FSC certification is available with Open Joist Triforce products.
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