Interior finishes help define the character of a space—and also can be significant factors affecting its environmental quality. Chemicals offgassing from interior finishes, particularly carpeting, was implicated in some early high-profile cases of “sick building syndrome.” From this discovery came a series of efforts to measure and control emissions from carpet and other finishes, so that today there are low-emitting options available in all finish categories. If finishes are applied while occupants are present, it is especially important to use low-emitting materials.
Finish materials also affect the environment before they’re installed, due to raw material extraction and impacts from manufacturing. Wall and floor coverings are replaced more frequently than the rest of the building and so their cumulative environmental impact can be substantial. Where feasible, choosing enduring design over a trendy look reduces the pace of replacement cycles, minimizing associated impact. Design that uses structure as finish, such as polished concrete, also reduces material use and environmental impact.
Emissions from paints and coatings
Paint, stains, adhesives, and other wet-applied coatings have their greatest effect on indoor air quality during and immediately after installation. The health hazard is particularly acute for installers. Most conventional products off-gas volatile organic compounds (VOCs), and other chemicals that are added to enhance the performance or extend shelf life of the product. Little scientific data is available on the health effects of many of these chemicals—and even less on the effects of exposure to a combination of such chemicals that may occur in buildings. Quality substitutions, which are lower in toxicity or nontoxic, are available for all of these products.
Some wet-applied products continue to emit VOCs for a long time after installation. In addition, VOCs emitted during curing can become attached to other surfaces in the space, especially fabrics, and then be re-emitted over time. To reduce this problem, painting should be done with soft surfaces covered and direct ventilation provided until the coating is dry.
Flooring options abound
Flooring and floorcoverings are subject to physical abuse from feet and heavy objects, and, because they’re the lowest spot in a room, they tend to collect dirt, moisture, and other contaminants. A good flooring material should be very durable—to reduce the frequency of replacement—and it should be easy to clean. Some spaces are suited to polished concrete which reduces overall material use by eliminating the need for added finish flooring. At the same time, softer surfaces may be preferred for comfort, noise absorption, and style.
Flooring is made from a wide range of materials, including wood, bamboo, cork, terrazzo, masonry, tile, along with VCT, linoleum and other resilient flooring materials, each with a unique environmental profile. For example, VCT and vinyl sheet flooring are widely used and have a low initial cost. However, maintenance requirements and costs can be high, and there are significant environmental and health concerns from the PVC and phthalate content, and from the emissions of frequent stripping and waxing cycles.
When selecting flooring and floor coverings such as carpet, make sure that it doesn’t introduce harmful emissions into the space. On top of that, look for lower-impact materials and manufacturing processes.
Sustainable wood products
Whenever possible, woods used in interior finish and trim should be from certified well-managed forests. In GreenSpec we look to the Forest Stewardship Council (FSC) certification as the most responsible indicator that wood products of all types come from well-managed forests. FSC-certified bamboo and cork flooring is also becoming more available.
For most building materials, the terms “salvaged” and “reclaimed” apply only to materials that have been previously used and then collected for reuse. This definition applies to wood products as well, especially large timbers from old structures that are remilled for use as structural members or flooring. Be careful, though: some salvage operations, particularly river-bottom salvage, don’t count toward LEED credits and can cause habitat disruption.
Drywall and Backing boards
Conventional drywall is relatively low-impact in terms of manufacturing, but not all that durable, and the paper facing is susceptible to supporting mold growth. It is typically made from 100 percent recycled paper backing and natural gypsum, which is plentiful and can be low-impact to extract. More and more drywall today contains pre-consumer waste in the form of synthetic gypsum created by sulfur removal systems in the smokestacks of coal-burning power plants. This material is sometimes referred to as flue-gas desulfurization gypsum.
In selecting a backerboard product for wet areas, such as tub and bath surrounds, effective moisture-management should be the primary consideration. There are three major types of tile backer board appropriate for these applications: cementitious, coated glass mat, and fiber-cement.
Textile and vinyl wall coverings are commonly used in commercial buildings for sound control and durability. Paper and vinyl “wallpaper” is widely used in homes. Avoiding vinyl (PVC) products where there are reasonable alternatives is environmentally desirable for several reasons. Beyond the environmental and health concerns with PVC and the phthalate plasticizers used to make it flexible, most vinyl wall coverings have very low moisture permeability, so there is potential for mold growth if moisture is trapped behind these wall coverings. Consider synthetic and natural-fiber alternatives to PVC-based wall coverings.