The choice of building materials is a critical decision that can effects a building during design, construction, and its operation. A sustainable building is constructed of materials that minimize life-cycle environmental impacts such as global warming, resource depletion, and human toxicity. In addition, green building materials offer specific benefits to the building owner and building occupants such as:

• Reduced maintenance/replacement costs over the life of the building
• Energy conservation
• Improved occupant health and productivity
• Lower costs associated with changing space configurations
• Greater design flexibility

        Green building materials are composed of renewable, rather than nonrenewable resources. Green materials are environmentally responsible because impacts are considered over the life of the product. The efficiency of materials chosen may be maximized by meeting the following criteria:

• Recycled Content: Products with identifiable recycled content, including postindustrial content with a preference for postconsumer content
• Natural, plentiful or renewable: Materials harvested from sustainably managed sources and preferably have an independent certification (e.g., certified wood) and are certified by an independent third party
• Resource efficient manufacturing process: Products manufactured with resource-efficient processes including reducing energy consumption, minimizing waste (recycled, recyclable and or source reduced product packaging), and reducing greenhouse gases
• Locally available: Building materials, components, and systems found locally or regionally saving energy and resources in transportation to the project site
• Salvaged, refurbished, or re-manufactured: Includes saving a material from disposal and renovating, repairing, restoring, or generally improving the appearance, performance, quality, functionality, or value of a product
• Reusable or recyclable: Select materials that can be easily dismantled and reused or recycled at the end of their useful life
• Recycled or recyclable product packaging: Products enclosed in recycled content or recyclable packaging
• Durable: Materials that are longer lasting or are comparable to conventional products with long life expectancies

        Certain materials can enhance indoor environmental quality when they meet the following criteria:

• Low or non-toxic: Materials that emit few or no carcinogens, reproductive toxicants, or irritants as demonstrated by the manufacturer through appropriate testing
• Minimal chemical emissions: Products that have minimal emissions of Volatile Organic Compounds (VOCs). Products that also maximize resource and energy efficiency while reducing chemical emissions
• Low-VOC assembly: Materials installed with minimal VOC-producing compounds, or no-VOC mechanical attachment methods and minimal hazards
• Moisture resistant: Products and systems that resist moisture or inhibit the growth of biological contaminants in buildings
• Healthfully maintained: Materials, components, and systems that require only simple, non-toxic, or low-VOC methods of cleaning
• Systems or equipment: Products that promote healthy Indoor Air Quality by identifying indoor air pollutants or enhancing the air quality

        The use of efficient materials can also have an effect on other green design principles such as energy and water efficiency. Designing for and selecting efficient materials and resources help contribute to the synergy of a green building. The use, re-use, recycling, and salvaging of existing and recycled materials help in the reduction of waste, and is applicable through-out a building's life.