Assessing Green Building Materials: Page 2 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.

Toxins

Products that contain toxic ingredients are unhealthy. Many products that offgas toxins are commonly used in buildings. At best, any toxic ingredients in a product are deemed to be “stable” in their final form. But those toxic ingredients have effects and impacts in the manufacturing process and to construction workers that predate their “stable” form—and are likely to have effects after their useful life in the building.

Example: Even low-VOC paints and stains contain a wide range of chemicals that are toxic during manufacturing and in the home, including glycol ethers, formaldehyde, biocides, amines, monomers, acrylic polymer latex, titanium dioxide, ammonium hydroxide, benzisothiazoline, methyl-isothiazolin, benzene, and toluene.

Transportation

Products that travel long distances have larger environmental impacts because of fossil fuels used in their transport. The heavier the material and the longer the travel distance, the greater the impacts—especially for materials that are moved by trucks.

Example: Lumber is often shipped across the continent, and can sometimes double its travel distance as it makes its way from mills to distribution centers to retailers, resulting in high amounts of fuel used.

Planned Obsolescence

“Maintenance-free” often means that something will last for a specific length of time and then need to be replaced. Materials that require some maintenance can often be refurbished repeatedly over decades or even centuries, but most materials that require no maintenance cannot be repaired, and end up as landfill.

Example: Vinyl siding is often touted as being maintenance-free, but cracks, splits, and warping cannot be repaired. Within a couple of decades, entire vinyl siding installations will need to be replaced.

Complexity

Complexity in a product, assembly, or system often leads to malfunction, breakdown, and waste. When parts of a complex building fail, it can lead to cascading problems. Simpler systems that rely on time-tested principles tend to be more long-lived.

Example: Basement foundations in wet areas often rely on automated sump pumps, which have several components that can wear or fail and rely on a continuous electricity supply to function. When they do fail, flooring, walls, insulation, and mechanical devices in these spaces can be ruined. On-grade foundations keep all these elements well above the water line and don’t need any mechanical devices to stay dry.

Labor

Using human labor is more sustainable than machine-made or machine-installed. Both environmentally and economically, craftsperson work is the least impactful.

Example: Plasterers using local ingredients in a wet plaster sys­tem can have dramatically lower impacts than drywall, tape, and “mud” manufactured and shipped from a central factory.

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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