Assessing Green Building Materials: Page 5 of 5

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The notion of building green has become mainstream in recent decades, thanks to the efforts of a small number of builders on the fringe of the building industry.
High-performance doesn’t necessarily equate to “green”—for example, petroleum products, such as foam insulation, have high embodied energy and major impacts on ecosystems.
Concrete has advantageous building and thermal properties, but is high in embodied energy and very high in carbon dioxide emissions.
Lumber is a renewable resource, albeit slow to regenerate. Its embodied energy depends on the distance between origin and use.
Straw bales are an agricultural “waste” product, with low embodied energy and good thermal performance.
Forest products may travel long distances between their material harvest and end use, which drives up their embodied energy.
Often, it’s the final energy performance of the structure that dominates its classification as being “green.” But this is only one aspect of an ecofriendlier building.
Per ton-mile, ships use only 1.3% of the fuel consumed by trucks. However, goods are usually transported over longer distances, resulting in high embodied energy.
Trains use only 0.8% of the fuel used by trucks to move freight; shipping by train significantly reduces a product’s embodied energy due to transportation.
When available, natural building materials, sourced and processed locally, are often the best bet for “green” solutions.

Third-party certification programs for lumber can help you determine if forestry practices are in place to minimize impacts. If you buy uncertified wood, you have no idea where that wood is being harvested, what forestry practices are in place, and whether or not it was milled appropriately. Here are some tips for selecting “greener” lumber.

Keep it local.  If possible, visit the harvest site and the sawmill. Many small mills cannot afford to be certified “sustainable” by a third party, but still use very sustainable practices.

The Forest Stewardship Council (FSC) provides third-party certification of sustainable harvesting and processing of wood products. Lumber with an FSC certification is an indication that environmental impacts may be reasonable.

The Sustainable Forestry Initiative (SFI) is an industry organization founded as a response to the FSC. While they have made efforts to distance themselves from direct ties to the industry by diversifying their board, the lumber industry is still a central player. They have recently worked to be seen as a legitimate certification and have improved their standards to be similar to FSC.

Industry Pathways

The building industry is at an interesting junction. While most people realize that the status quo is becoming less viable, there is no consensus about what strategies and materials will lead the way.

New products are entering the market daily, all trying to improve upon the mix of environmental performance, affordability, durability, and ease of installation. None are perfect, but many are worth considering. Informed choices will go a long way to encouraging those with the highest environmental standards, helping to achieve buildings with high performance and low impact—and at an affordable cost.

Comments (4)

Byrdhouse9's picture

The article in the paper magazine includes a table called "Comparing Materials", showing the embodied energy per kilogram for various insulation materials. Is there data available that corrects for the fact that some kinds of insulation provide much more R value per unit weight than others? Light insulation like fiberglass and polyurethane foam would fare much better if the comparison showed energy per unit of R value.

Michael Welch's picture

Energy per R-value would be a great indicator to have.

Byrdhouse9's picture

There is a typo in the "Transportation Impacts" paragraph. The 0.3 gallons of fuel per ton mile for trucks should be 0.03. Typical mid-size trucks achieve this, and heavy trucks often do as well as 0.01 gallons per ton mile. For example, my old F-350 gets a pathetic 10 miles per gallon when hauling 3 tons, but that works out to 0.033 gallons per ton mile .

Allise Burris's picture

Sliding that decimal would mean that ships and trains consume approximately 10% and 30%, respectively, of the fuel required by trucks for the same tonnage. I believe the ~1% and ~3% numbers of the photo captions could be correct.

Also, do pickups and semi-trailers really achieve nearly the same fuel efficiency by weight carried? Or do we define "heavy" trucks differently?

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