Understanding Green Building Costs:
Life-Cycle Analysis and Assessment (LCA) of Building Green
Environmental Costs
The environmental costs of a project refer to the impact that your building project has on the natural world, and on the communities that are involved in producing and, ultimately, disposing of your building materials. Understanding the environmental costs of your project is in many ways an inexact science, and it certainly isn't a job just for you, the building owner. It is a job for your architect and your builder (and for the builder's sub-contractors and vendors) as well. But it is your job to raise the questions, and when appropriate raise, too, the consciousness of your project partners.
Whether you're considering the environmental costs of wood products from Indonesia, pre-formed siding from France or paints from the U.S., the questions you might ask are the same. Be aware that it is not always easy for your project partners to know all the answers to these questions…but remember that by asking them you are serving to raise the awareness and accountability of everyone involved, both for this project and for future practice.
Origin of products and materials
The first set of questions to ask are about the origin of the product or materials used in your building. What is the substance of which these materials are made (wood, stone, fiber, etc.)? Is this material harvested, quarried or extracted in a way that is sustainable, or in a way that is healthy or harmful to the local environment, workers, the local population? What industrial processes, chemicals, or tools are used in this extraction process, and are they safe for workers and protective of the environment? A number of organizations and institutions GreenFaith has worked with add a social justice dimension to this inquiry by asking if the workers involved are paid a fair and living wage.
Manufacture of products
The next set of questions address the product's manufacture, where many of the same kinds of questions are relevant. Does the manufacturing process create pollution? How is the pollution handled, and who is impacted by it? Does the manufacturing process create health risks for workers or the surrounding community? How are these risks reduced? What kind of waste is created, and is it toxic? How and where is the waste disposed, and is this done in a safe, healthy manner?
Comparison of products and materials
A third set of questions focus on your use of different building materials or products. What is the material’s or product’s purpose? Could that purpose be equally well served by other materials or products with lower "environmental" costs or impacts? Will the product’s use improve or worsen your building's impact on the people who will use it (for instance, through releasing unhealthy chemicals breathed in by your building’s occupants over a period of time)? Will its use improve or worsen your building's impact on your neighbors, your community, or your watershed - for instance, through rainwater run-off that adds to local stream pollution, this affecting the quality of drinking water)? Will its use improve or worsen your building's global warming impact (for instance, through the amount of greenhouse gas emissions created by its energy use)?
Probable lifespan of products and materials
We recommend that you ask about the probable lifespan of the products and materials used in your building. This is a question with multiple implications. If the materials or products are ones that help you reduce your energy costs or your carbon footprint, will they last for a long time? If certain materials or products are less beneficial --perhaps because a suitable green alternative isn't yet available or affordable--will you be able to replace these items in the near future as alternatives become available? Environmentally benign products with long life spans help you reduce your building’s environmental impact because you do not often need to create additional raw material or energy use for replacement purposes.
Disposal of products and materials
We also recommend that you ask questions about what happens to your building materials when they are disposed of. When these materials have reached the end of their useful lives, how and where can they be recycled or disposed of? What impact on the environment will their disposal have? How toxic might that disposal be?
Embedded energy in products and materials
Finally, we suggest that you ask questions about reducing the “embedded energy” that your building contains. “Embedded energy” refers to the energy that is used in the process of extracting, refining, manufacturing and transporting your building materials. From an environmental perspective, the lower the embedded energy of your building, the better. Understanding the concept of embedded energy can help you to weigh alternatives, such as reusing wood from a structure which you are expanding or renovating rather than simply disposing of it.
Ideally, your architect and/or builder should be able to answer these questions for you – particularly if one or both of them are LEED-certified professionals. Don’t be shy about asking these questions – by asking, you send your architect and builder the message that you understand the concept of environmental costs, and that you want to minimize your building’s negative impacts on the earth.