Materials

Choosing the right materials is a complex task even without considering the environmental and health impacts of extracting, manufacturing, shipping, living with, and disposing of each product. Life cycle analysis of individual materials has provided several rules of thumb for different categories of materials. And a growing and maturing market for green, high-performance materials now offers durable products that address indoor air quality concerns, avoid toxics, and minimize waste. The prices of many of these materials are becoming competitive with conventional products.
bq. A green materials strategy
Recycled and resource efficient products
Source locally and sustainably
Purchase to protect air quality
Avoid toxins

A green materials strategy

Start with a purchasing strategy that addresses health and environmental concerns. Set criteria based on existing guidelines, standards, and certifications, and review material safety data sheets (known as MSDS) for new products and all proposed substitutions.

The first steps in greening materials use are to reduce the amount used and to reuse existing buildings or deconstruction debris. For an overview of material-saving and reuse techniques, as well as durable construction techniques and products, see the Waste page. Below you will find more detail on recycled and low-waste materials.

Recycled and resource efficient products

Recycled-content building products are now available for everything from paint to concrete to lumber. Many of these recycled products perform better or are cheaper than conventional equivalents.

• Specify recycled-content percentages for products and materials based on existing guidelines and availability. Provide product names if possible, and look for options with high post-consumer content. Look for reclaimed materials, too.
• Can it be recycled? Buy durable products and materials, but also give preference to those that can be reused or recycled at the end of their useful lives. This is more important for heavy use materials like flooring and countertops.
• Look for these recycled materials:
  • Recycled rubber and polymer roofing imitates slate and reduces weight and maintenance.
  • Recycled glass and concrete materials are now available for durable countertops, backsplashes, shower surrounds, walls, and floors.
  • Recycled plastic lumber for decking.
  • Recycled latex paint (made from unused paint) can cut costs.
  • Concrete made with fly ash and recycled aggregate base is stronger, cheaper, and more workable.
  • Recycled steel framing can replace lumber in most applications and has numerous advantages in strength, durability, and workability.
  • Recycled carpet, drywall, insulation, ceramic tile, pavement, and related materials.

Resource-efficient materials reduce material use, cut labor costs, and often perform better than the traditional alternatives.

• Finished materials. Choose materials that do not require on-site finishing.
• Pre-cut or pre-assembled components can reduce lumber use by 25% and overall construction costs by 15% due to labor savings.
  • Use pre-cut (I-joist) or pre-manufactured (truss) floor and roof framing.
  • Use panelized wall framing and/or roof systems.
  • Employ modular construction for the whole building.
  • Structural Insulated Panels (www.sips.org) are gaining acceptance for use in walls, floors, and roofs. Panels sandwich a rigid foam core (usually expanded polystyrene) between oriented strand board (known as OSB). OSB mixes wood strands made from fast-growing trees with wax and a binder to form mats. These mats are layered across each other for strength, then heat-pressed into panels that makers say save time and energy over stick-built construction.
• Engineered lumber can be made from smaller branches and trees species that would otherwise go to waste. It resists warping, cracking, and splitting better than conventional lumber.

Source locally and sustainably

• Locally-produced materials have lower transport costs and benefit the regional economy. The expanding market for green products has given rise to local businesses across the U.S. that manufacture from recycled content, use alternative materials, or supply salvaged building products.
  • Use locally-produced products and materials where possible. Set a goal of at least 20% for materials manufactured (not just distributed or assembled) with 300 miles of the building site.
  • Take advantage of locally sourced stone and wood for architecture rooted in the building's location. It is much easier to know if a forest 50 miles away is sustainably managed than one that is located halfway around the globe.
• Wood. The building industry uses a large amount of lumber and finish wood materials, much of it harvested unsustainably. By choosing environmentally certified wood, especially that with the Forest Stewardship Council mark, you support well-managed forests. Other responsible options include salvaged wood (from riverbeds in addition to old buildings), engineered, and composite lumber, and bamboo, which makes great flooring. Avoid old growth timber and endangered tropical species.

Purchase to protect air quality

Building materials choices have their greatest impact on indoor air quality. Selecting the right finishes, flooring, ductwork, and insulation ensures that living spaces do not expose residents to dangerous chemicals or allergens.

• Low- or no-VOC products. Volatile organic compounds (VOCs) include health hazards such as toxic solvents and formaldehyde and contribute to ground-level ozone pollution. Select paints, primers, sealants, and insulation that minimize off-gassing of VOCs.
  • Paint and finishes. High quality, no-VOC paint options are now available, as are many low-VOC paints and finishes. Specify solvent-free, no-VOC, or Green Seal rated products. These will significantly reduce odors, too.
  • Sealants and adhesives can continue to off-gas hazardous chemicals years after installation. Choose low-toxic, low-VOC products and request MSDS sheets to check for chemical risks.
  • Insulation. Some new fiberglass insulation is VOC-free; other lung-friendly insulation includes recycled cotton batts (containing cloth trimmings usually scrapped) and soy-based sprayed-in foam.
• Carpet not only harbors dirt, dust, mites, and mold, but it also requires glues that often off-gas VOCs. Wood and linoleum flooring is more durable and easier to maintain, although careful selection of finishes and glues is important. Carpets made from recycled PET or durable nylon are preferable, as are fiber and waffle carpet pads or the more durable brands of integral-cushion carpet (with a peel-off sticker-like back). Maintenance is important to keep carpets from harboring dust and other allergens.
• Choose insulation, carpet pads, refrigerants, foam sealants, and fire suppression systems (plus any other potential ozone-harming source material) that are not made using halons, CFCs, or HCFCs.
• Vinyl is very toxic. It will off-gas for months after installation and presents a serious health risk in the case of fire--more than the fire itself in the case of vinyl siding. For flooring, opt for natural linoleum or tile. Both are durable and not resource-intensive to produce.
• Install metal ductwork, not fiberglass, and keep it clean during construction.
• Engineered wood products have many benefits, but should meet standards for formaldehyde emissions.

Avoid toxins

Toxic substances are often used as preservatives, fire retardants, finishes, and sealants for building materials. These toxins are released throughout a product's life and pose a risk to construction crews working with recently treated materials, residents who come into contact with the substances daily, and the surrounding environment.

• Pressure-treated lumber often contains arsenic and chromium, two highly toxic elements that seeps into soils. Choose the less toxic ACQ treatment over the traditional CCA and switch to composite decking or recycled plastic lumber for areas where children will play or where food is grown or served.
• Avoid formaldehyde. Check particleboard, fiberboard, plywood, and joint compound.
• Non-toxic cleaning products are widely available and cost competitive. Specify low-toxic or citrus-based products and encourage residents to consider cheaper, benign options like vinegar, baking soda, and borax. It is important to educate residents and janitorial staff on proper use.