- safer material selection
- material sourcing
- embodied carbon
- construction waste diversion
Sustainable design includes the informed selection of materials and products to reduce product-cycle environmental impacts while enhancing building performance. Describe efforts to optimize the amount of material used on the project. Outline materials selection criteria and considerations, such as enhancing durability and maintenance and reducing the environmental impacts of extraction, manufacturing, and transportation. Identify any special steps taken during design to make disassembly or reuse easier at the building’s end of life. What other factors helped drive decision-making around material selection on this project?
Materials selection is perhaps the most clearly defined responsibility of an architect, and yet the goals for sustainable materials are varied and occasionally mutually exclusive. Traditionally, materials were selected for durability and accessibility. First-generation sustainable metrics sought to reduce waste, favor regional materials, and reduce VOC’s. Second-generation goals add the dimensions of reducing embodied carbon, providing transparency about their ingredients, and avoiding chemicals of concern. Architects are working closely with manufacturers to develop new materials that are sustainably sourced, “Red List”–free, and fully transparent. Currently, there is a wealth of resources to help architects specify materials that have gone through rigorous third-party vetting to ensure health, safety, and limited environmental impact. These resources, a few of which are referenced below, save valuable research time and allow architects to provide a layer of quality control on their material selections.
Safer material selection
- Select “chemicals of concern” to exclude from the finished project. You can either choose an established list, such as the ILFI Living Building Challenge Red List, or create your own. To get started, choose just one chemical of concern to avoid in a project (such as vinyl, lead, or formaldehyde), then improve from there.
- Review the chemical components that make up the products you are specifying. As with food labeling, lots of ingredients with long unpronounceable names are a good indication of hazardous chemicals. When chemical components are not available, ask the manufacturer to provide them, or choose a different product that values transparency.
- Set goals for material selection criteria around health, and be sure that the contractor is on board. Require that the contractor is documenting progress toward the goals during the entire construction process. This information should be reviewed monthly during payment review to ensure material tracking goals are met.
- Require material impact tracking (Environmental Product Declarations [EPDs] or similar) from the contractor during the construction process. This information should be reviewed monthly during payment review to ensure material tracking goals are met.
- Extract or source products in a responsible manner. Wood should be certified by the FSC, and other materials (such as stone, metal, and concrete) should be extracted in a way that does not scar the landscape or damage the natural environment. When working with stone, understand the implications of its extraction.
- Focus on bio-based (organic) materials whenever possible; when harvested sustainably, these products are perpetually available. Wood, linoleum, cotton and bioplastics are a few examples. It is important that these products meet the Sustainable Agriculture SAN (Sustainable Agriculture Network) Standard.
- Identify opportunities for material reuse, such as salvaged materials or materials with high recycled content, such as most metals. Percentage of recycled content can be reviewed with the manufacturer.
- Identify products with an extended producer responsibility, such as a manufacturer that has a take-back program. This will ensure that the full life cycle of the product is considered.
- Always begin developing a materials palette based on what is available locally. The website DistanceFromTo will help determine material extraction or manufacturing distance (if the project has a goal of using products from within a certain radius).
- Choose products that promote fair trade, respect for human rights, and other equity practices in disadvantaged communities.
- Part of the architect's responsibility when it comes to material selection is to work toward more equitable, healthier environments for those affected by manufacturing. Products with dirty manufacturing processes, and manufacturers that impose unjust labor practices, should be avoided. Research is required here, as ignorance will usually result in supporting labor or manufacturing practices that might not align with the goals of the project. Strategies in this area include avoiding LBC’s Red List materials and studying manufacturers’ corporate sustainability reports.
- A Whole Building Life Cycle Analysis (LCA) is like an energy model for a project’s materials. Running an LCA will help to determine which materials have the greatest environmental impact, allowing the design team to make targeted improvements. Links to tools for preparing an LCA are listed below.
- Wood, when harvested sustainably, contains less embodied carbon than concrete or steel. Using wood as a building’s major structural system, in the form of gluLams (glued laminated timber), cross-laminated timber (CLT), or similar system, will significantly decrease a building's total embodied energy.
- Portland Cement has a high embodied energy compared to other cementitious materials; therefore, the goal for low-carbon concrete is to use as little Portland Cement as possible—or eliminate it entirely. Specify concrete with a high supplementary cementitious material (SCM) content. Options include fly ash, slag, pozzolan, lime, and many others.
- Use of regional, recycled, and salvaged materials is a great strategy for reducing embodied carbon.
- Choose insulation with low embodied carbon such as cellulose or mineral wool. The embodied carbon of most plastics-based insulation tends to be high.
Construction waste diversion
- Reduce construction and demolition waste disposed of in landfills by recovering, reusing, and recycling construction and demolition debris. Set goals and develop strategies with the contractor.
- Require waste-tracking by the contractor during the entire demolition and construction process. This information should be reviewed monthly during payment review to ensure waste-diversion goals are met.