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.
Some materials provide a better alternative in an application dominated by products for which there are concerns about toxic constituents, intermediaries, or by-products. With the panoply of products made with polyvinyl chloride (PVC) and brominated flame retardants, some products are green simply because they provide an alternative. Examples of this are natural wall coverings, drain and vent piping, and roofing membranes. Some green products are free of hazards common to the product category; for example, LED lighting is inherently free of the mercury found in fluorescent lighting sources.
However, it’s worth noting that without transparency about actual ingredients, there’s no guarantee that a product won’t have less common or less well-known hazards that the manufacturer isn’t talking about. We use Pharos’s Chemical and Material Library to assess less well-known hazards, and we encourage manufacturers to review the hazardous properties of all chemicals they use and seek out safer materials.
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.
Just how low the VOC level needs to be for a given product to qualify for inclusion in GreenSpec depends on the product category. For most products, we require certification to California’s health-based emissions standard, CDPH Std Method v1.1 standard (also referred to as California Section 01350), which tests a product’s resultant VOC concentrations in the space after a given period of time. For wet-applied products like paints, caulks, and adhesives, we still also look for VOC content instead of, or in addition to, verified low emissions; this is because emissions testing doesn’t adequately test initial offgassing, and VOC content is currently the only widely available proxy.
While resilience—the ability to weather natural disasters and maintain livable conditions in the aftermath of disruptive events—is mostly an issue of building design and community preparedness, certain products can help. For example, almost all heating systems require electricity to operate even if their primary fuel is oil, gas, or wood pellets; systems that allow operation even if grid electricity is not available are more resilient in the event of power outages. Rainwater harvesting, water storage, composting toilets, and waterless urinals contribute to resilience not only in drought-prone areas but also during power outages in any home dependent on well water. Solar water heating systems that can operate without utility power, and back-up power systems that are more energy-efficient than standard generators, may have this attribute.
SureHard is a clear, colorless blend of liquid silicates chemically engineered to react with the lime in concrete, forming an insoluble gel in its pores. On a concrete slab, SureHard provides dustproofing, densifying, sealing, and hardening, as well as waterproofing and increased reflectance. Concrete surfaces treated with SureHard may be diamond polished for a polished concrete floor. SureHard is applied with a water-based solution with no VOC content. It is also non-flammable, low-odor, and non-toxic.
Installing and maintaining common flooring materials—such as vinyl composite tile, carpeting, and terrazzo—add significant environmental and financial costs to a structure over its lifespan. Structural concrete that is already in place can double as finish surface, creating attractive flooring that mitigates those life-cycle impacts.
Polished concrete floors combine diamond stone-polishing technology and silicate chemical treatment to create a highly durable, nearly maintenance-free surface that does not require repeated applications of VOC-laden waxes or other potentially hazardous coatings. Pioneered in Sweden in the 1990s, polished concrete is created by grinding concrete until level and smooth, adding silica-based densifiers, and polishing using increasingly finer abrasives. The silicates fill the pores and react with the concrete to make it dense and less porous. This concrete can then be polished to the desired sheen to create a finished product. Low long-term maintenance costs—no maintenance beyond regular cleaning should be needed—help make polished concrete among the least expensive flooring options available.
Three of the most common densifiers in North America are sodium and lithium silicates and colloidal silica. Sodium silicate is inexpensive but requires rinsing after densification, generating alkaline wastewater that has to be disposed of appropriately. Lithium silica requires no rinsing and cures quickly. Colloidal silica (nanoparticles of amorphous silica suspended in solution) penetrates deeply and is more reactive than either sodium or lithium.
GreenSpec generally does not encourage the use of nanomaterials, but colloidal silica is approved by the FDA as an anti-coagulant in food and has been used extensively in industry since the 1950s. It should react completely with the concrete and not present a hazard. Overall, evidence suggests it is relatively safe, though all densifiers have to be handled and applied appropriately.
GreenSpec lists concrete polishing systems and supporting products, including water-based, zero-VOC densifiers.
GreenSpec also lists pigments, including recycled materials and mineral byproducts of industry, and concrete stains—typically a blend of acrylic polymers and pigments; surface-applied dyes that can be mixed or diluted to create custom colors; and color hardeners, blends of pigments, silica sand, wetting agents, and portland cement that are worked into freshly placed concrete to densify and color the surface.
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