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Green building not only saves energy but helps reduce the three billion tons of raw materials that are turned into foundations, walls, pipes, and panels every year. In fact, the building construction industry is the biggest user of materials, including steel and cement.
Reducing the need for raw coal minimizes one of the most environmentally-
destructive processes of the entire energy sector — mining. Mining often
involves mountaintop removal and produces acid mine drainage caused by exposing
iron- and coal-bearing rocks to water.
These disheartening facts do not even consider building waste. The editor of Environmental Building News, describes construction and demolition (C&D) waste as “one of the most daunting challenges we face in the construction industry Disposal costs are high, resources are needlessly wasted, and we are running out of landfill space. Even though there has been considerable media attention given to the solid waste crisis, Wilson comments that “it is remarkable how little we really know about C&D waste.” There are few reliable statistics on quantities of C&D waste generated nationally, and just a few studies of the composition of this waste.
Remodeling Project Comparisons:
It is especially difficult to assess total waste generation for renovations because of the wide variation in the types of remodeling jobs. The Table above, shows the results of five waste assessments that have been made at residential sites in the US, showing a wide variety of generation rates on a square-foot basis.
The National Association of Home Builders (NAHB) avoided this discrepancy by estimating the amount of material produced by the type of remodeling project. In the US, the major waste generated during remodeling activities stems from kitchens, bathrooms, and room additions. Annually, there are approximately 1.25 million major kitchen remodeling jobs (complete tear out), with average waste generation of 4.5 tons per job. Americans perform 1.5 million minor kitchen remodeling jobs (facelift, cabinet replacement, etc.), that generate 0.75 tons of waste per job. Major bath remodeling (1.2 million per year) produces on average 1 ton of waste material each, and 1.8 million minor bath remodeling jobs produce on average 0.25 tons of waste each. Room additions, estimated at 1.25 million per year, produce about 0.75 waste tons apiece. From these calculations, NAHB estimated total residential renovation waste generation, from improvements or replacement projects, to be 31.9 million tons per year.
In the US, construction and demolition debris account for 20 percent of all landfill waste; 43 percent ( million tons) of this total is from residential construction, demolition, and renovation projects. The number of landfills in the United States is steadily decreasing — from 8,000 in 1988 to 2,300 in 1999. Creating new landfills is limited due to the protests of area residents near proposed sites. As a result of landfill limitations, the disposal costs are soaring to an average of 2 to 5 percent of the overall budget costs, or $511 per house for construction disposal. These costs drive more and more people to illegally dump construction and demolition waste.
Reduce, Reuse, Recycle
Green building provides myriad ways to dramatically reduce your waste and the costs associated with disposing it. Did you know that 85 to 90 percent of construction disposal is recyclable? If you plan with the 3 R’s of waste reduction (reduce, reuse, and recycle) in mind, you will definitely see economic benefits. To this end, green remodeling encourages three key steps: planning ahead of time; reusing materials wisely; and recycling building waste.
The first step is planning. For minimizing the amount of waste generated, the following main areas should be focused upon: dimensional planning and design, material use and recycling, and use of modular/pre-constructed elements along with other resourceful building techniques. Since you may need to outsource this work, it is essential that the design team establish the waste reduction goals in contractual form with the subcontractors. Since contracts are often sidestepped (either purposely or inadvertently), it is the job of the construction manager to oversee all work and verify its successful completion.
Poor planning and design results in insulation leaks, moisture, rot, insect infestation and added waste — leading to added costs ranging from higher energy and waste removal bills to the worst-case expense of evacuating and demolishing a mold-infested house. The extra energy and resources needed for repairing poorly planned buildings also contribute to the deterioration of the quality of our water, air and land.
Second, as you will read, green remodeling helps you use resources more wisely. We can build structures durably out of energy-efficient materials, including reused and recycled products. Some examples are engineered lumber, which reduces the amount of material needed by as much as 50 percent without sacrificing strength; walls built from insulation sandwiched between panels of oriented strand board; and recycled-content building products such as carpet, decking, cellulose, and fiberglass insulation.
Third, recycling waste helps to keep resources out of landfills. As an incentive to builders, many local municipalities are beginning to collect used construction materials at solid waste transfer stations with little or no tipping fee. Some non profit recycling or reuse organizations will come to the site and load waste materials, often offering the builder a tax receipt for the donation.
Although there would seem to be no reason not to reduce, reuse, and recycle, the construction industry is a conservative one. New green technologies, products, and procedures typically take time to establish their stronghold. However, in our capitalist society the construction industry will adapt more quickly to a change in demand for green products. Homeowners who choose to make a difference and embrace green remodeling, therefore, have a huge potential to green the building industry and save precious natural resources.
Residential construction accounts for more than 50 percent of the wood consumed in the United States; 30 percent of softwood lumber (pine) consumption is accounted for by remodeling and repair alone. Wood is durable, beautiful, and renewable. Compared to steel and concrete, wood also uses less energy; creates less air, water, solid waste, and greenhouse gas pollution; and uses fewer ecological resources. However, we still waste wood unnecessarily and we need to be more reflective about the types of wood that we use. In particular, wood harvested from virgin, endangered, or old-growth forests should be avoided.
Old-growth forests take hundreds and even thousands of years to reach maturity and are home to innumerable plants and animals found nowhere else. To date, we have harvested over 97 percent of North American old growth forests. Of that, one third goes into lumber, plywood, particleboard, and other structural building material.
Although the extraction process for wood is less polluting than that for many other building materials, we must consider the quantity of wood extracted compared to steel and plastics. Global consumption of industrial timber (approximately i.66 billion tons per year) exceeds the use of steel and plastics combined. The average US home requires about 15,000 board feet of lumber, the equivalent of harvesting an acre of trees. Humans are deforesting the world at a rate of 37 million acres a year (approximately the land area of Finland) 63 As a result of this high rate of timber consumption globally, forests are not just declining in area, but also in quality. As recently as 20 years ago, the average old- growth tree harvested from US national forests was 24 inches in diameter. Today the average is 13 inches! Globally, we also lose an estimated 27,000 species annually because of habitat loss, and the building industry is largely responsible.
FYI: Although the US is home to only 4.5 percent of the global population, it is responsible for over 15 percent of the world’s consumption of wood.
Use Less Wood
In recent years, there has been a strong movement towards using wood more efficiently in construction in order to minimize wood consumption and the cost of wasted materials, as well as to optimize energy savings. By understanding the common dimensions available for building materials, we can quickly see what dimensions can be incorporated into design to reduce waste. Plywood, oriented strand board (OSB), and rigid insulating sheathing all come in four-foot by eight-foot dimensions. If you build in two-foot increments (outside dimension to outside dimension), there will be less wood sheet waste because the two-foot dimension is divisible by both the four-foot and eight- foot factors. This is applicable for wall construction, roofs, and overhangs.
For maximum framing efficiency, 24 inches on center (o.c.) spacing between framing members should be used instead of the standard 16 inches o.c. In other words, if you have studs (vertical pieces of wood) spaced 24 inches apart as opposed to spacing them 16 inches apart, you use less wood along the length of any given wall. If your wall is 12 feet long, you can build 24 inches o.c. with seven studs (144 divided by 24 + 1). If you build 16 inches o.c., then you have to use ten studs. When you’re adding on multiple walls, you can see how the wood savings from building 24 inches o.c. quickly add up.
When you construct with 24 inches o.c., you typically use two-by-six pieces of lumber for framing. These are usually more expensive than two-by-fours used with 16 inches o.c., and the volume of material is roughly the same. However, the 24 inches o.c. two-by-six method uses about 30 percent fewer pieces of wood, translating into labor savings and greater wall cavity space for more insulation. and more insulation equates to more energy savings. The typical R value (rate of heat loss through a material) for two-by-fours is 13, whereas for two-by-sixes, the R value is 19. This difference can save a significant amount of energy!
Additionally, you can also couple the 24-inch frame spacing with other efficient measures, including two-stud corners. Often builders use up to four studs at a corner, but this method merely wastes material, since you only need two. Also, the entire corner is wood with four studs — a “thermal bridge,” or area with minimal insulation resulting in greater heat loss. Using two studs enables you to install more consistent insulation. In turn, the two-stud corner lends a higher R value and can save you money on lower energy bills.
Not all timber is created equal: some is harvested with care and knowledge of valuable ecosystems, while some is the product of clearcuts and deforestation. A forest is very different from a tree farm or a plantation forest. Once a forest has been clearcut, the fundamental ecology is changed, from the micro-organisms in the soil to the diversity of fauna and flora. In other words, a tree farm is much like a cornfield: it is not a native habitat for the original species that once inhabited the area. Therefore, when we do use virgin wood, we should buy wood that is certified as being sustainably harvested, thus supporting environmentally appropriate, socially beneficial, and economically viable management of the world’s forests and encouraging lumber companies to adhere to sustainable forestry guidelines. Certified wood is becoming increasingly commonplace; you can even find it in places such as Home Depot.
Keep in mind there are numerous certification programs, and some are more reputable and reliable than others. The Forest Stewardship Council (FSC) was launched in 1993 by indigenous groups, timber companies and environmental organizations in an effort to standardize the emerging programs. FSC is an international nonprofit organization established for the purpose of creating a verifiable international standard for well-managed forests and a process for tracking and certifying products derived from those forests. Significantly, certification is a third-party process — in other words, the people certifying the forest operations are not forest owners or managers, whose biases may cause them to overlook forest management inadequacies. Most environmental groups, the U.S. Green Building Council, and progressive businesses recognize FSC as the only environmentally and socially credible certification program in existence at this time. Over the past ten years, 104 million acres in more than 40 countries have been certified according to FSC standards.
Rapidly Renewable Wood
All wood is renewable to a degree — which is one reason why wood is such a sought-after material for green construction. However, just as there are more efficient appliances for the home than others, there are also more renewable species of trees than others. Fast-growing trees offer the general benefits of plants (helping replenish oxygen in the air, and removing harmful CO but also offer a consistent supply of material for construction.
There are many different species of wood used in construction that are highly renewable, with varying uses and applications based on geography, building codes, and availability. For instance, bamboo reaches up to a height of 60 feet in the first several months, making it extremely fast growing and renewable. Its strength is unmatched relative to its weight as compared to other construction materials. Although it is rarely used as frame construction in North America, it is commonly used in other areas of the world. Bamboo has successfully been adopted as a green flooring material due to its quick regrowth, and resulting consistent supply. Aspen is another rapidly renewable tree, but its uses are limited to engineered lumber products such as oriented strand board (OSB), because of its limited strength.
Alternate, Under-utilized Tree Species
In the Table below, opposite, the left-hand column lists examples of endangered, vulnerable and rare tree species that you should avoid purchasing. For example, ipê, like many other trees in the tropical rainforests, only occurs in densities of one or two individuals per acre throughout most of its natural range. To meet the orders for hundreds of thousands of board feet of FAS (“fine and select” or “four side-clear,” meaning no knots or defects on all four sides of the board for its entire length), loggers have to log thousands of trees. That means punching roads and skid trails into thousands of mostly pristine acres of old-growth rainforests, as well as damaging or destroying up to 28 trees for every one they target. The canopy is reduced by about 50 percent after loggers take the mahogany, ipê, jatoba, and a few other high-value species for export. The right-hand column in the Table will help you identify and specify alternative, under-utilized species to expand your design options and extend the forest resource. By using lesser-known species in lieu of the handful of “standards” we now depend so heavily upon, we can alleviate pressure on species that are threatened with extinction from over harvesting. We can also dramatically improve the economics of sustainable forest management by demonstrating the value of the full panoply of forest resources. This, in turn, will provide an incentive to maintain the wide diversity of species in natural forests.
What Trees are OK to Use?
1. Prior to specifying any tropical wood, reference the CITES listing of endangered species.
2. Harvested from forests that have been certified as “well managed” according to standards endorsed by the Forest Stewardship Council.
In addition to rapidly renewable certified wood, homeowners should consider engineered wood as they remodel their home. Today’s building industry is limited to younger, smaller trees that yield little sizable lumber. Much of this new wood tends to be weaker and wetter, with more natural defects and less tensile strength. However, unlike these smaller trees, engineered wood can utilize the strongest fibers. New technologies can take a tree apart and put its fibers back together to take advantage of its natural strengths wherever they are found on the tree. Using trees too small for sawn lumber, they can produce engineered lumber that’s bigger and stronger than anything cut from a tree today. The result is a structural system of high quality lumber that’s superior to the original log in size, strength, and dimensional stability.
Not only does this process avoid the use of old-growth trees, but the manufacturing process converts as much as 75 percent of a log into structural lumber compared to less than 50 percent by conventional methods using fewer trees to do the same job. Making the most of under-used fiber, they produce cost-effective, readily available lumber that maximizes underused resources and minimizes environmental impact. In addition, engineered woods are able to use wood from readily available and quick-growing trees such as yellow poplar and aspen.
Significantly, engineered wood should still be certified. Most wood utilized for engineered wood is extracted using clearcut logging practices. Approximately 1.2 million acres are cleared annually to operate 140 chip mills in the Pacific Northwest. According to the US Forest Service, the removal of softwoods is currently exceeding the growth rate in southeastern US states. FSC-certified wood — whether virgin or engineered — ensures proper management and longevity of our precious forests.
Non-forest sources of wood are another alternative to virgin or old-growth lumber. Reclaimed wood is salvaged from buildings and structures that are being remodeled or torn down. Sometimes logs that sank decades ago during river log drives can even be salvaged. Reclaimed wood is desirable from an environmental perspective because it is not associated with recent timber harvesting, it reuses materials, and it can reduce the construction and demolition load on landfills. Additionally, reclaimed wood is often available in species, coloration, and wood quality not found in today’s forests. But, as with other resources, the supply of reclaimed wood is limited, therefore efficient and appropriate use of reclaimed wood is important for its long-term availability.
Overall, whether you choose certified rapidly renewable, engineered, or reclaimed/salvaged wood, avoid selecting wood that has been treated with chromated copper arsenic (CCA) or ammoniacal copper arsenate (ACA). Arsenic is a rat poison. Treating wood increases its durability in locations where degradation by rot or insects might occur. However, leaching of chemicals out of the wood into the surrounding environment may occur to a limited extent. Handling the wood can also pose a risk to human health, especially if the chemical treatment is not fully dry. This is particularly a problem for young children who might be playing on a treated wood deck or playground equipment. Roughly 17 percent of all softwood lumber is pressure-treated today, including about 40 percent of all softwood from the southeastern U.S. From 1985 - 97, approximately 48 billion board feet of wood products have been treated with CCA. The Environmental Protection Agency classifies wood treated with these substances as hazardous waste.
The most significant environmental concern associated with preservative- treated wood is disposal by incineration. Currently, an estimated 2.5 billion board feet of preservative-treated wood is disposed of annually; as much as i6 percent may be incinerated. Toxins, such as arsenic, may become airborne to a limited extent, but most toxins end up as ash where they are highly leachable. One tablespoon of ash from CCA lumber is enough to kill a cow. Unfortunately, the only environmentally acceptable disposal option for CCA-treated wood is to send it the landfill, and these are filling up.
Although CCA was phased out of production for residential use in December 2003, it will remain an issue for existing homes. To avoid problems with CCA-, treated wood, try to ensure that treated wood is disposed of in lined landfills only, so that it does not pollute the soil and water. Better yet, try to reuse treated wood so it does not end up in a landfill in the first place. Use construction details that minimize the use of wood in locations where rot or insect infestation is likely. If wood must be used, a healthier alternative is Alkaline Copper Quarternary (ACQ), which does not contain arsenic or chromium. Borate preservatives are also much less toxic, but can somewhat leach out of wood in wet conditions. You might also consider naturally rot-resistant species like cedar or redwood, but only if they are from a certified forest.
Recycled Plastic “Wood”
Plastic lumber, a newer and increasingly popular replacement for CCA pressure- treated lumber, is most effective because it protects timber resources and prevents the use of highly toxic lumber treatments. It also provides a use for the millions of tons of annual plastic waste. Plastic lumber will not rot, absorb water, splinter, or crack; it is also resilient to shock, making it an extremely durable component in exterior applications. Plastic lumber is most cost-effective in large-dimensions where wood is most expensive, but should not be considered a suitable replacement for load-bearing structural components.
Composite lumber incorporates some of the characteristics of wood with those of plastic lumber. Recycled wood waste fiber is combined with recycled plastic resins to create a product that has some improved strength and aesthetic characteristics. Like plastic lumber, it will not rot, crack, or splinter. Furthermore, wood composite materials generally have a more natural coloring and appearance, although they may still be stained or painted. In general, plastic and composite lumber are great options to consider for decks or other exterior applications
When remodeling we must also consider another increasingly valuable resource — fresh water. According to the Worldwatch Institute, buildings in the United States use 17 percent of the total freshwater flows. Large quantities of water are required to produce many construction materials: during manufacturing, steel uses 25 times more water than wood. More generally, our water consumption has almost quadrupled since 1940. US indoor residential water use is estimated to average 8o gallons per day in homes without efficient fixtures. Outdoor use varies tremendously, but obviously adds significantly to this number.
In the Middle East, China, India, and the United States, groundwater is being pumped faster than it is being replenished, and rivers such as the Colorado and Yellow River no longer reach the sea year round. Fresh water in groundwater often takes centuries or millennia to build up — it has been estimated that it would require 150 years to recharge all of the groundwater in the United States to a depth of almost 2,500 feet if it were all removed. Issues over water rights create conflict between neighbors, counties, states and countries. Water issues also force us to dam rivers and irrevocably damage countless ecosystems: “In the northern hemisphere, three-quarters of the flow from the world’s major rivers has been tamed to quench our thirst.” Bjorn Lomborg, author of The Skeptical Environmentalist: Measuring the Real State of the World, reasons that our water wells are not going to run dry; in fact, even projected “overestimates” of total water use for 2025 require just 22 percent of the readily accessible, annually renewed water.’ But when we consider its uneven distribution and the environmental degradation caused by pollution and damming, it becomes clear that better water management practices are essential to providing clean water for everyone while preserving fresh water ecosystems.
Better water management can begin in the home. While domestic use only accounts for a small fraction (12 percent) of total water use, it is still problematic. For example, rapid urban growth has resulted in depleted ground water sources in Los Angeles, San Diego, and Tucson, forcing these cities to siphon water from far-reaching places. However, with minimal impact on our current lifestyles, we can reduce our domestic water use by as much as half. Today’s water-saving showerheads and faucet aerators save water by creating a more forceful spray, sometimes mixed with air, using less water. Low-flush toilets, required by code in the U.S. for new construction use, use 1.6 gallons of water or less per flush. Composting toilets are also an option; they can save a typical family of four 47,028 gallons of water per year. Additionally, modern dishwashers can fit on a countertop and use only 4.75 gallons of water per wash cycle. Newer front loading washing machines are initially more expensive, but use only 20 to 28 gallons per load as opposed to 45 gallons and save $60 to $100 per year in water and energy costs.
Outside, we can take steps to lower the water needs of our lawns. One solution is to use wildflowers, low-water native plants, and attractive xeriscape designs. Not only do these plants lower water use, they also save time and money because of fewer maintenance requirements. If giving up a traditional grassy lawn is unappealing, simply plant buffalo grass, which requires less water than traditional lawn grasses. Finally, instead of installing a conventional sprinkler system, use drip irrigation. Drip irrigation delivers water directly to the plants’ roots rather than wastefully spraying water over a large area, where much of it evaporates.
Although our planet is 71 percent water, humans depend on a mere 0.65 percent of this water for survival — much of which is polluted. In a recent article in The Washington Post, it was reported that “about a quarter of the nation’s largest industrial plants and water treatment facilities are in serious violation of pollution standards at any one time.” Moreover, half the serious offenders exceeded pollution limits for toxic substances by more than 100 percent.
According to the Natural Resources Defense Council, an estimated 7 million Americans are made sick annually by contaminated tap water; in some rare cases, this results in death.
Many Americans worry about drinking tap water: we spend over $4 billion per year on bottled water and over $2 billion per year on in-home water filtration systems. We do not recommend bottled water for several reasons:
It’s wasteful. According to a Los Angeles’ Times report, “If the [ water bottle waste ] problem continues, enough water bottles will be thrown in the state’s trash dumps over the next five years to create a two- lane, six-inch-deep highway of plastic along the entire California coast. In an April 2002 report by the World Wildlife Fund, an estimated 1.5 million tons of plastic is manufactured from petrochemicals each year to package water. The EPA estimates that in 2000 alone, about one million tons of plastic bottles ended up in US trash bins.
It’s just tap water. National Resources Defense Council and Consumer Reports have found that some bottled water is simply tap water. In can be worse for you, in fact: tests by Consumer Reports in August 2000 showed that plastic water containers can leach phthalates and other chemicals into the water, and bottles that are left open for long periods are subject to bacterial growth and contamination. Unlike tap water, regulations allow bottled water to contain E. coli or fecal coliform and don’t require disinfection for cryptosporidium or giardia.
It’s expensive. Bottled water can cost from 240 to 10,000 times more per gallon than water from the faucet, according to calculations by the Natural Resources Defense Council. In the US, we pay more for bottled water than we pay for gasoline.
Water filters are the best option for contaminated water. First, you need to figure out what’s in your water. In a May 2002 study of the nation’s stream water by the US Geological Survey, scientists discovered chemicals found in drugs, detergents, disinfectants, insect repellants, plastics, and personal care products, including 33 suspected hormone disruptors. If your water source is “good,” the easiest and least expensive option is to select a charcoal filter that removes the chlorine taste and smell, as well as excess minerals and possibly some heavy metals. For water that is contaminated with pollutants such as pesticides and harmful chemicals, consider systems for reverse osmosis and distillation. The Environmental Protection Agency (EPA) estimates that the cost of providing state-of-the-art drinking water via water filtration systems would cost the average household only $30 per year. (Learn more about water filtration in the Plumbing section of this web site)
Aside from using water filters, there are several other options. You can boil water for a minute to kill bacteria and parasites. You can drink and cook with only cold water and let the water run for one minute in the morning to decrease lead from pipes in old homes (although this option wastes water). Or you can leave tap water in an open container in the refrigerator for few hours to dissipate chlorine and trihalomethanes (THMs).
Ultimately, the best defense against water pollution is to protect the rivers, streams and wetlands that are the source of your drinking water. Campaign to limit development around reservoir watersheds. Refuse to use yard pesticides and fertilizers that can run off or seep into groundwater. Dispose of leftover paints and other household chemicals through your community’s hazardous waste collection program — don’t pour them down the drain. Use biodegradable cleansers and detergents, and buy organic food that is grown in accordance with watershed- protecting farming practices. Small actions add up to a big difference!