DES040A – Christina Cogdell
March 14, 2016
Tiny Houses: The Katrina Cottage
The tiny house movement is a charge toward minimalist living, distilling housing to its barest modern idea and constructing structures of high utility. Through the efficient use of space, generally from 100 to 1,000 square feet, each area must be accommodating to daily use rather than purely formal function. Walking in to one of these homes puts a visitor directly in the center of a family's lives, no halls, no parlors. Care is taken to design a space that is adaptable by simplifying elements that are essential and foregoing expectations of layout that have built up over the centuries of American home architecture. Design focus on the most essential needs of everyday life allows for increased quality of interactions (Wyatt). Minimal use of materials and efficient use of space makes a tiny house design an ideal component of a disaster relief effort.
This practice began in large scale from the San Francisco earthquake of 1906, in which thousands of poor refugees were suddenly in need, when the city had no established plans to accommodate those that could not move or stay with other family – the working people that made the city flourish, and were needed to help rebuild. Lingering in make-shift tents months and years after the quake, they needed a permanent solution. The response of the U.S. Army, volunteers, and the then newly formed Red Cross was to construct small buildings of a standardized design by the thousand, made from wood but without foundation. The houses could be purchased on a rent-to-own model, and the owner would then be responsible for taking the house from the construction area and planting it on their land. These were an affordable solution, and several of these 5,000 homes have lasted to today.
When hurricane Katrina struck the Gulf Coast in 2004 millions were displaced (Shelter), but the government had a plan to help. The Federal Emergency Management Agency (FEMA) contracted the construction of 102,000 trailer homes (McIntosh) that could be made in a factory and easily transported to where they were needed. These were temporary structures, designed to last under two years, and were payed for by loan to the families that needed them. This proved insufficient, not only did people lose their family homes, they were again put in to debt with a structure that would only last through the short term and took a great deal of maintenance to continue functioning safely. The FEMA plan failed to revitalize the area and resulted in a lawsuit when they began loan collection years after they were still stuck in the failing trailers.
A local response was the commission of architect Marianne Cusato to design a structure that could house a small family, withstand hurricane force winds, and be accommodating to long term use and expansion: the 308 sq. ft. Katrina Cottage. These structures played to the Creole heritage style of the area and were feasible to be constructed by a few skilled workers. Further pushing the practical ideal, plans and materials for this Katrina Cottage could be purchased at any Lowes store in the area. Collaboration with a national chain granted access to a robust transportation and acquisition network that kept prices reasonable and the design accessible to multitudes of people. For what FEMA would loan to many receiving their temporary trailers, around $70,000, a permanent, livable structure could be built that would suffice for the long term.
The failure of the New Orleans levee system instigated by hurricane Katrina left approximately 80% of the city in flood conditions of up to fifteen feet, rendering most homes that survived the winds uninhabitable. As part of the revitalization effort, the construction of new homes with modern techniques introduced an avenue of improvement over the aging infrastructure of the city. Marianne Cusato's Katrina Cottage was designed to withstand hurricane force wind, and to make use of modular and factory construction techniques.
Only necessary materials were shipped to self-building operations, and bulk use in factory conditions worked to make excesses minimal. The final material composition of the cottage was variable, with Cusato's plans a template for people to build off of rather than an absolute. Roofs were variably produced of metal sheets or asphalt shingles, and foundations could range in compositions from concrete slabs or stilts to wheeled trailers. Ultra efficient Lcynene insulation could be used, an expanding foam that is cheaply transported in liquid form and is environmentally friendly relative to the materials it replaced. Insulated concrete foundations with steel reinforcements give longevity to a home as well as increased energy retention and ease of installment as a trade-off of simpler foundations.
Cusato's base design revolves around a Lumber frame and siding, as well as an interior of plywood and drywall. The foundation, if employed at all, was variable from a concrete slab to vertical concrete forms, stilts, or even mobile trailers. Modern insulating windows impeded humidity and sun damage, also deterred by vinyl exterior paint.
Katrina Cottages came to fruition through two forms, as factory-made prefabricated components, or raw materials and paper plans. Several plans were available ranging in size from 300 to 800 square feet.
When a customer purchases a materials package for a Katrina cottage, for which the cost of plans is forwarded, it is delivered by truck in several installments as construction progresses. Lowes handled the post-Katrina material distribution of self-built Cusato's cottages, using their network to direct materials from across the nation to where they were needed. Much of America's lumber production is cheaply available in southern states, making the primary building materials readily available. This as well as bulk factory building conditions worked to lower materials usage below average home construction wastes at the cost of a high degree of transportation.
At the micro level, self-build operations were highly successful and common. Those with experience could manage and oversee the training of inexperienced families to help them build their homes (Stohr). This was largely accomplished in groups, resulting in communities forming in the process of revitalization. Lack of skills and experience can lead to waste, but the scale of these cottages enabled people to work without the assistance of large, impactful, and costly equipment.
With insulation and a smaller volume to care for, little or no air conditioning is required to retain comfortable temperatures. This generality extends to other utilities in the home, less things results in less power draw. Luxury appliances are not to be found in the 308 sq. ft. areas.
With their new homes, families need new appliances. Modern Energy Star devices are commonly available and when replacing whole areas such as in rebuilding efforts, the energy intake of the area is drastically reduced when replacing aging appliances. New codes of electrical wiring and plumbing were also employed to reduce waste, in most cases professionally installed whereas previous structures may have only been retrofitted by owner.
This focus on growth and utility is what makes tiny houses practical – they don't make assumptions about the owner's needs beyond the essential. Through expansion or regular maintenance alone the life of the home can last through generations of occupants, and as a permanent structure its lifespan is indefinite. As a replacement for temporary FEMA trailers, designed to last less than two years, these homes were far more affordable from the onset and in required maintenance, which would be comparable to an average stick-built home as opposed to planned obsolescence.
The small area of the house remains robust and practical for a small family. Though it lacks capability to support luxuries, the family could build additions to the cottages, which was incorporated into the architectural design from the forefront. This responsiveness reduces potential waste when applied over a large number of homes.
Questions arise in the practicality of smaller homes, fixed costs of utilities and space needed for single-use areas like kitchens and bathrooms drive up the cost per square foot, impeding the rate of return when downsizing; it may not be financially reasonable to build a tiny house on an expensive plot for land owners (Evans). Yet, for revitalization efforts or otherwise purely as personal choice, the minimalism they employ is attractive and inexpensive relative to an average modern home, and a valuable replacement to the aging homes of the area.
As a replacements, these cottages are designed to exceed modern building codes and could outperform the efficiency of most original family homes thanks to their insulation, weather resistance, and consideration of flood levels. Modern utility routing techniques and appliances also lend towards increasing the efficiency of the whole effected area.
Regulations include restrictions on the size of homes, from local zoning (Pflaumer) to international treaties of living standards that define necessary rooms, amenities, and square feet (IRC). These specifications designed to increase quality of life also stand to limit access to practical as context changes over time.
An enumerated materials list for the Katrina Cottage was not available at the time of writing. As such an accurate life cycle assessment could not be performed, any data presented are estimations.
Evans, Lynette. The little house that roared. San Francisco Chronicle. Published 2006.
McIntosh, Jacqueline. The Implications of Post Disaster Recovery for Affordable Housing. Published 2013. http://dx.doi.org/10.5772/55273
American Tiny House Association. “Zoning.” Accessed February 1, 2016. http://americantinyhouseassociation.org/category/type/zoning/
Pflaumer, Drew H. “Tiny house handbook.” Modified May 2, 2015. http://cardinalscholar.bsu.edu/handle/123456789/199621
FEMA. “Robert T. Stafford Disaster Relief and Emergency Assistance Act”. Modified April 2013. https://www.fema.gov/media-library/assets/documents/15271
FEMA. “Mississippi Alternative Housing Pilot Program.” Modified May 8, 2015. http://www.fema.gov/mississippi-alternative-housing-pilot-program
IRC. “Minimum Room Areas.” Modified 2012. http://publicecodes.cyberregs.com/icod/irc/2012/icod_irc_2012_3_sec004.htm
Stohr, Kate. Design Like You Give a Damn. Edit Architecture for Humanity. Published January 15, 2006.
Shelter and Housing. A Failure of Initiative. Accessed February 3, 2016. http://govinfo.library.unt.edu/katrina/shelterandhousing.pdf
Wyatt, Anne. "Rethinking Shelter and Tiny House Communities: Dignity Village, Portland, and Lessons from San Luis Obispo." Modified 2014. http://digitalcommons.calpoly.edu/focus/vol11/iss1/14
The Energy Embodied in the Katrina Cottage
In 2004, Hurricane Katrina brought destruction, death, and despair to the Gulf Coast. In the wake of the Hurricanes destruction there existed an urgent and pressing need for disaster relief, and one problem involved providing housing for a large number of displaced people. The Federal Emergency Management Agency described the hurricane as "the single most catastrophic natural disaster in U.S. history” (8), and was overwhelmed with applications for temporary housing requests, which included hotels stays. The use of trailer homes by FEMA to house those afflicted proved to be an unsustainable solution as the trailer homes were expensive to purchase, expensive to maintain, and were not designed to last for very long. The fact that families were required to take loans to purchase these trailers proved to another reason the FEMA trailers failed spectacularly. There existed a need for housing that would be inexpensive, and would also serve to lift the spirits of the disaster afflicted people. The Katrina cottage arose as response to the failure of the FEMA trailers, a cottage that served as an alternative for people of the post Katrina world. A solution that succeeded where FEMA had failed.
The Katrina Cottages were conceptualized and designed by architects Marianne Cusato, Steve Mouzon, and Bruce Tolar to address the failings of the FEMA trailers. The most well received of the designs were those drawn by Marianne Cusato, and addressed the shortcomings of the FEMA trailers by offering an inexpensive yet permanent structure that was aesthetically pleasing and stayed true to the regions architectural roots. The Cottages were small in size, ranging from 300 to 1000 sq/ft in size. Their modular design allowed them to be expanded upon if needed. Plans for the cottages as well as construction materials were available at Lowes, and the simplicity if design allowed for them to build by local contractors or even by the homebuyers themselves. The houses were designed to be energy efficient, and for the most part required the same materials required to build a regular house, just in smaller quantities.
In this paper I will examine the forms, amounts, and source of energy that were involved making this cottage a reality, from the extraction and processing of raw materials, to the transportation and of said materials and their eventual assembly.While Katrina cottages are no longer distributed by Lowes, the plans for the original as well as updated variants of the Cottage can still be purchased, therefore for the purpose of this paper I will research the energy involved in the assembly of the cottage in Davis, California where with a large student community, there might be a demand for this form of housing in the future.
Embodied energy is the energy consumed by all of the processes associated with the production of a building, from the mining and processing of natural resources to manufacturing, transport and product delivery. Embodied energy is the ‘upstream’ or ‘front-end’ component of the life cycle impact of a home (5). The precise calculation of embodied energy is difficult, expensive, and varies with each specific project as differences in transport distances, geographical location and other factors change calculations drastically. A precise calculations is beyond the scope of this paper, however along with examining the form, amount, and source of energy, I will make tentative estimates based on energy calculators I found during my research process.
Energy in manufacturing materials.
The essential materials used in the Katrina cottage was lumber, for the structure, and metal for the roofing. Lumber uses the least embodied energy compared to other building materials such as brink and concrete. A relatively green product if harvested from sustainably managed forests. The process energy requirement of embodied energy for kiln dried Hardwood would measure 2.0 MJ/KG.
The process of bringing lumber to its finished form begins with the felling of trees, usually with gasoline-powered chainsaws, and trimming of branches and limbs. I called the local Davis Hardware store Hibberts, and learned that most lumber comes from a warehouse nearby. Further research into timber production yielded information that, in 2006, 91 percent (1.5 billion board feet) of California’s total timber harvest (1.7 billion board feet) came from the North Coast, Northern Interior, and Sacramento regions. Historically, these regions have provided more than 85 percent of California’s timber harvest(4), and most timber used by California’s industry was harvested from within the state, with additional volume coming from Oregon. Tractors and trucks are used to load the felled logs, which are then transported to the lumber mill. At the mill a conveyor belt is employed to saw logs to predetermined lengths, and further cut and trimmed to a variety of sizes. The lumber then undergoes the most energy intensive phase of the production, which is the industrial drying phase, to prevent decay and to allow the wood to shrink. The final stage in manufacture is the passing of the wood through a planer, where the surface is trimmed and made smooth (1). The machines and vehicles employed in the manufacture and processing of lumber run on secondary sources of energy, namely petrol and electricity. The finished material can be purchased at Hibbert’s Lumber in Davis.
The roofing of the cottages is made of metal sheets. Galvalume coating prevent rust and corrosion of the metal roof, which is known to last up to four times as long as shingles. Aluminum sheets make a fine choice as a roof as it can be manufactured with over 30% of recycled steel post-consumer content, qualifying it for LEED credit given by the green building council(2). The PER embodied energy for Aluminum is 170 MJ/KG, with the number certain to increase as Aluminium is processed further to create the finished product of stamped roofing sheets.
The primary raw material from which Aluminium is extracted is Bauxite, a clay like soil often imported from Jamaica and South America. At a manufacturing facility, the bauxite is crushed and heated with caustic soda and lime, using natural gas as energy source for heating. This treatment of bauxite allows for the extraction of Aluminium oxide.
The next step in the process is smelting, and this step requires the intensive use of electricity. Since large amounts of electricity is required, some primary aluminum smelters can be found in areas with lower-cost electricity, often in areas with rich hydroelectric resources, such as the Pacific Northwest and Upstate New York(6). Aluminium oxide is treated to form metallic aluminum using large steel vats, electricity, and two oppositely charged electrodes. The vat has a carbon lined bed and a carbon rods placed at the top, both of which serve to act as electrodes for current to pass between. Alumina is dissolved into molten cryolite at temperatures of 960-970° C to form an electrolyte solution. A direct current is passed through the solution which serves to break the bonds between aluminum and oxygen atoms, with oxygen collecting at the carbon rods forming carbon dioxide, and aluminium collecting as a molten metal at the base of the pot. The liquid Aluminium is then cast in to slabs, ingots, or foundry alloys (3).
Slabs of galvanized aluminum are coated with chemicals Kynar 500 or Hynar 5000, before being rolled into coils, which are treated to accept multiple layers of paint. The coils are then passed through a stamping press, which creates rolls of ready to install roofing sheets. Aluminium rolls are distributed to retailers all over the United States, with many distributors stamping the rolls themselves. Metal roofing can be procured at Hibbert Lumber or Ace Hardware in Davis.
Energy in Construction
Calculating energy in construction is based in the transport of materials to the site and the assembly into the final product. The transportation costs in terms if energy would be negligible as materials can be purchased at Hibbert’s Lumber and Davis is a small town, and a single truck would suffice to transport the materials to the construction site. The prime movers are humans as the Katrina cottage can be assembled without heavy construction equipment, however power tools would likely be employed, which would make us of electricity. To offer some perspective, I employed the use of an embodied energy calculator for a 500 Sq/ft cottage, which performed calculations for total energy spent in the production of the cottage, from the manufacture of materials to their delivery and construction (7), in an arbitrary area other than Davis, and the resulting calculation brought a figure of 310,000 MTBU of embodied energy.
Energy in Maintenance
The energy use of a Katrina Cottage per year would be around 10-15 MMBTU, and around 400- 600 MMTBU over a 40 year period, which would include minor maintenance and repair. Secondary sources of energy such as electricity would primarily be used for the energy needs of the house.
In conclusion, researching the energy required to manufacture two of the primary materials required to construct the Katrina Cottage yielded insight into how costs and energy can be saved while still creating a shelter that people can be proud of. The Katrina cottage serves as a model for the future as we move forward in a world that has to address the increasingly urgent issues of overpopulation, exploited resources and climate change. A model of how scaling back can actually be the new way to make real progress.
1. "Lumber." How Lumber Is Made. N.p., n.d. Web. <http://www.madehow.com/Volume-3/Lumber.html>.
2. Roofus. "How a Metal Roof Is Manufactured - Metal Roofing Info - MetalRoofs.Info." Weblog post. Metal Roofing Info MetalRoofsInfo. N.p., 13 June 2014. Web. <http://www.metalroofs.info/how-a-metal-roof-is-manufactured/>.
3. "How It's Made." How Aluminium Is Made. N.p., n.d. Web. <http://www.hydro.com/en/About-aluminium/How-its-made/>.
4. Morgan, Todd A., Jason P. Brandt, Kathleen E. Songster, Charles E. Keegan, and Glenn A. Christensen. "California’s Forest Products Industry and Timber Harvest, 2006." Forest Service: General Technical Report (n.d.): n. pag. Bureau of Business and Economic Research. United States Department of Agriculture, Aug. 2012. Web.
5. "Embodied Energy." Admin_666. N.p., n.d. Web.<http://www.yourhome.gov.au/materials/embodied-energy>.
6. "U.S. Energy Information Administration - EIA - Independent Statistics and Analysis." Energy Needed to Produce Aluminum. N.p., n.d. Web. 09 Mar. 2016. <https://www.eia.gov/todayinenergy/detail.cfm?id=7570>.
7. "Welcome to the May T. Watts Appreciation Society Embodied Energy Page." Welcome to the May T. Watts Appreciation Society Embodied Energy Page. N.p., n.d. Web. 15 Mar. 2016. <http://thegreenestbuilding.org/>.
8. "Hurricane Katrina Statistics Fast Facts." CNN. Cable News Network, n.d. Web. <http://www.cnn.com/2013/08/23/us/hurricane-katrina-statistics-fast-facts/>.
14 March 2016
Wastes and Emissions of a Katrina Cottage
Although it’s been nearly 16 years since Hurricane Katrina struck the American South, its notoriety continues to credit it as being one of America’s most destructive natural disasters. Hurricane Katrina was the cause of over 1200 deaths and $75 billion worth of damages.1 With widespread flooding throughout Louisiana and Mississippi, there was an overwhelming need for short-term housing in affected areas. In response, FEMA signed contracts with Pilgrim International, Coachman Industries, and Gulf Stream Coach for 120,000 trailers.2 Meant to serve as safe, temporary shelters for Katrina victims, over the years, FEMA trailers developed the opposite reputation. Linked with causing the local epidemic of respiratory infections, high formaldehyde emissions from the particleboard used in these trailers made them unfit for living.3 In an effort to provide a long-term solution to these short-term trailers, Marianne Cusato designed a series of tiny homes marketed as Katrina Cottages—model KC-308 being the smallest with 308 sq. ft. of living space.4 Although materially, they’re comprised of the same materials as everyday American homes, these houses are notably smaller in scale.5 Cusato’s design made efficient of use of materials and space, minimizing the environmental impact mass construction of these homes would create. This paper will focus on the wastes and emissions of wood, drywall, and asphalt roofing—the basic structural components of a Katrina Cottage—created during the material production, home construction, and long-term management of KC-308.
Wastes and Emissions of Material Production:
Many strides have been made in the manufacturing of wood construction products, asphalt roofing shingles, and drywall to minimize waste and emissions produced.
Three basic wood products are used in the construction of KC-308—lumber, plywood, and OSB.6 Production of all three products requires debarking of tree logs. All this bark is then recycled into use for fuel or mulch.7 Typically lumber production creates the most wood chip waste, with plywood coming in second. After breaking down waste wood chips into their cellulosic fibers and resin, they can be treated with wax and other binding components to make medium-density fiberboard (MDF).8 OSB production, on the other hand, uses the entire shaven log.9
Asphalt shingles are produced by impregnating a fiberglass mat with asphalt and applied with rock granules.10 Asphalt is a black, liquid substance that is a byproduct of processing crude petroleum. Other than the airborne contaminants produced by the fuel used in powering machines that grind gravel, production of rock granules yields comparatively low waste. The materials list for Cusato’s plan gives homebuilders the option of choosing what time of roofing they want to aesthetically customize their home. Homebuilders can choose between strip asphalt roofing shingles, dimensional asphalt roofing shingles, and premium asphalt roofing shingles. Though they comprise largely of the same raw materials, strip asphalt roofing are single-layered asphalt roofing shingles and thus, contain less material. Therefore, manufacturing and reroofing them produces the least amount of waste compared to dimensional asphalt roofing shingles and premium asphalt roofing shingles.11
Drywall is made using gypsum paper sandwiched with plaster. Traditionally, gypsum is mined. However, the introduction of Flue-Gas Desulfurization (FGD) gypsum--a byproduct of desulfurization of flue gas from the stacks of fossil fuel plants--helped make the production of drywall a lot more sustainable. FGD gypsum has the exact same chemical composition as naturally occurring gypsum but has helped divert 8 million tons fossil fuel waste that would've ended up in landfills. Currently, half our nation’s production of drywall uses FGD gypsum paper however further implementation is being made. Paper used in drywall is made from 100% recycled newspaper.12
Wastes and Emissions of Housing Construction:
A startling 40% of America's solid waste comes from construction sites. On average, 8,000 pounds of waste is created for every 2,000 square footage of home.DirtySecretThe majority of this waste is comprised of wood, cardboard and drywall. Oftentimes, contractors order excess materials—be it lumber, plywood, OSB, or drywall—and throw away the extra, unused materials. Cardboard from material packaging is often thrown away unrecycled. Large efforts need to be made in streamlining this process. Although I lacked the resources to determine whether material amounts were overestimations of what’s needed to build a KC-308, the concept of standardizing orders for construction materials intrigued me. Intended for construction on a mass scale, provides one option as to how we can cut back on waste during housing construction. Analyzing materials lists prior to ordering presents a possible solution as to how we can cut back on wastes and emissions created during housing construction. Other solutions include considering materials for more than one use, working with suppliers whom you’ll be buying in bulk to cut back on packaging, seeking out suppliers with a buy-back policy, keeping to standard measurements, buying “finished” products, and identifying local recycling centers for waste that is produced.13
Wastes and Emissions of Housing Maintenance and Destruction:
Although the strength of OSB and plywood has proven to be equivalent, OSB absorbs moisture a lot more readily than plywood. Combined with the fact that it takes longer to dry, OSB use should only be limited to certain parts of a housing structure (i.e. walls and roofing) to avoid structural ridging.14 Therefore, although OSB may be a "greener" alternative than plywood from a production standpoint, knowledge of proper use of OSB is needed to maximize the lifetime of a house.
The majority of roofing waste comes from re-roofing. Tear-off waste shingles make up 85-90% of the waste and it's this portion that recycling efforts usually focus on. After these shingles are ground up and picked free of nails, they are processed into becoming pavement.16
Clean drywall scraps from construction sites have the option to be recycled--19% of recycled drywall is subject to close loop recycling whereas 81% is subject to open loop recycling. Close loop recycling implies the recycled drywall is taken back to the same production plant it was produced whereas open loop recycling implies it’s taken to a different production plant. Although drywall recycling is an option, the reality is that 64% of drywall that ends up in landfills comes from construction sites. Demolition makes up 14%, manufacturing 12%, and renovation 10%.17
In researching wastes and emissions produced in material production, housing construction, and housing maintenance and destruction of a typical Katrina Cottage, I was largely impressed with efforts dedicated to minimizing waste in the first two categories. However, I was shocked at the amount of unnecessary waste produced during housing construction. Overall, a life-cycle assessment of KC-308 yielded fairly little waterborne and airborne wastes. Although my choice source articles often referred to them, waterborne and airborne wastes were arbitrary when compared to the amount of solid waste produced during housing construction. Fortunately, the implementation of Katrina Cottages have made strides for the Tiny House Movement—a countermovement in response to America’s ever increasing home sizes. Downsizing is key in making the housing industry more environmentally sustainable as long as homebuilders erecting these tiny homes are mindful of the amount of their construction waste.
1 "Hurricanes in History." Hurricanes in History. National Hurricane Center, Aug. 2005. Web. 14 Mar. 2016.
2 Smith, Heather. "People Are Still Living in FEMA’s Toxic Katrina Trailers — and They Likely Have No Idea." Grist. Grist, 27 Aug. 2015. Web. 14 Mar. 2016.
3 Urbina, Ian. "Banned Trailers Return for Latest Gulf Disaster." The New York Times. The New York Times, 30 June 2010. Web. 14 Mar. 2016.
4 Custom, Marianne. "Mariannecusato." Mariannecusato. N.p., n.d. Web. 14 Mar. 2016.
5 "Building Materials List." Building Materials List. N.p., n.d. Web. 14 Mar. 2016.
6 "Building Materials List." Building Materials List. N.p., n.d. Web. 14 Mar. 2016.
7 How It's Made--Lumber. Dir. Gabriel Hoss. Discovery Channel, 2012. Youtube.
8 "NON-WOOD FOREST PRODUCTS." The International Forestry Review 1.2 (1999): 121. Environmental Protection Agency. Mar. 2015. Web. 14 Mar. 2016.
9 Lisette, Paul. "Choosing Between Oriented Strandboard and Plywood." UMass Amherst. University of Massachusetts Amherst, 2005. Web. 14 Mar. 2016.
10 How It's Made—Asphalt Shingles. Dir. Gabriel Hoss. Discovery Channel, 2012. Youtube.
11 "Asphalt Roofing Shingles." CertainTeed. CertainTeed, n.d. Web. 14 Mar. 2016.
12 "Drywall." How Drywall Is Made. Made How, n.d. Web. 14 Mar. 2016.
13 Bittle, Joel. "Home Construction's Dirty Secret: 8,000 Lbs of Waste Per 2,000 Square Foot House - Green Building Elements." Green Building Elements. Green Building Elements, 08 Jan. 2009. Web. 14 Mar. 2016.
14 Lisette, Paul. "Choosing Between Oriented Strandboard and Plywood." UMass Amherst. University of Massachusetts Amherst, 2005. Web. 14 Mar. 2016.
15 "From Roofs to Roads: Recycling Asphalt Roofing Shingles Into Paving Materials." (n.d.): n. pag. Environmental Protection Agency. Web. 14 Mar. 2016.
16 "usepa, Oswer, Office Of Resource Conservation And Recovery" "Drywall." EPA WARM Analysis (n.d.): n. pag. Environmental Protection Agency. Mar. 2015. Web. 14 Mar. 2016.
17 "usepa, Oswer, Office Of Resource Conservation And Recovery" "Drywall." EPA WARM Analysis (n.d.): n. pag. Environmental Protection Agency. Mar. 2015. Web. 14 Mar. 2016.