Mobile-Home Park Makeover
Last year a dilapidated trailer park on the Torres-Martinez Indian Reservation near Thermal, California, narrowly escaped being shut down due to what officials called Third world living conditions. The U.S. government and the Bureau of Indian Affairs pushed for closure of the 40-acre park, nicknamed Duroville, citing a host of problems: unsafe trailers, dangerous electrical wiring, leaking sewage, and piles of debris, all of which posed a threat to its roughly 5,000 residents, most of them migrant farmworkers. The federal judge hearing the case ruled in favor of the tenants, claiming that relocating them “would create one of the largest forced migrations in the history of this state.”
Enter Kenny Dickerson, owner of Palm Desert Masterbuilder, Incorporated, with a plan to rebuild Duroville. He was prompted by the plight of Wesa Torres, a single mother of three abandoned boys whom she adopted. Wesa is a member of the Torres-Martinez tribe and owner of a 10-acre allotment equipped with a well and a septic tank. She lives on it in a trailer that Dickerson deems unlivable. He is in the midst of building her a green home, funded entirely by donations of both materials and labor. He hopes it will serve as a template for the bigger project he now has in mind—to demolish all the trailers in adjacent Duroville and replace them with 298 close-to-zero-energy-use homes.
For Wesa Torres’s new four-bedroom, 1,800 ft2 house, he is using insulating concrete forms (ICFs) made by Reddiform, a New Jersey–based company. These rigid-foam forms hold concrete in place during curing and remain part of the structure, providing thermal insulation for concrete walls. Reddiform’s one-piece, all-foam, screen-grid blocks are made entirely of expanded polystyrene and in appearance resemble elongated blocks. The upper and lower edges have “teeth” for securely interconnecting adjacent blocks. They’re symmetrical and can be placed without regard to top or bottom, front or back, left or right. The foam itself provides excellent insulation with an R-value of 21, which remains constant. The blocks are lightweight, tipping the scale at only 3 lb each, and each one provides a wall surface equivalent to 4½ concrete blocks. Dickerson chose this particular material as part of his plan to achieve energy-efficient, durable construction. (A study conducted for the Portland Cement Association in 1997 showed that homes built with ICFs require about 40% less energy to heat and about 30% less energy to cool than conventional wood-framed homes. See “Foam Brings Concrete Results,” HE July/Aug ’98, p. 27. More-recent studies show around 20% cooling energy savings. See “ICFs Under the Microscope,” HE Nov/Dec ’02, p. 36.) For aesthetics, a sandstone spray will be applied to the exterior of the Torres house, and an orange peel drywall spray will be applied to the interior.
Since the desert community of Thermal is subject to triple-digit summer heat, as well as winter nights that can see temperatures dip into the 30s, an effective heating-and-cooling system is essential to the project. Dickerson is installing an A/C system developed by a company out of Denver—it’s known as a Coolerado (see Figure 1). It bills itself as the most-efficient air conditioner made, with an energy efficiency ratio of 40. The Coolerado is essentially a high-tech evaporative cooler, but the comparison stops there. Whereas a typical evaporative cooler adds humidity in the process of cooling a dwelling, the Coolerado unit does not. This is no small consideration for the Torres house. Although the desert climate is mainly dry, humid periods are not unheard of and are often made more intense by irrigation systems on surrounding farmland. The Coolerado unit sits outside the house on a concrete pad, taking in fresh air through a large duct. It filters the fresh air, cleans it, and then sends it through. It uses no chemical refrigerants, and its cooling capacity increases as the temperature rises. It uses up to 90% less energy than conventional systems.
The Federal Energy Management program (FEMP) published a report in March 2007 backing up Coolerado’s claims. It concluded “widespread deployment of this technology in average to dry climates in the United States could have a significant positive impact on electric demand and ease the burden on the utility grid.” In 2009, Colorado Governor Bill Ritter presented the company with the Governor’s Excellence in Renewable Energy award.
As for heating the Torres house, Dickerson says he will most likely install a propane unit in the attic that will convey hot air through the same ducts as the A/C. Given the climate, and the thermal insulation offered by the walls, he doesn’t anticipate a great need for heat. “It would be a rarity for it to even be turned on,” he says. Speaking of the attic, Dickerson sought to decrease the solar energy absorbed by the roof that radiates heat downward toward the attic floor. Since this is new construction, he installed plywood radiant-barrier sheathing (available in panels) directly underneath the roofing material, incorporating an air gap, so that much of the heat radiating from a hot roof is reflected back toward the roof. Particularly effective in hot sunny climates, this radiant barrier will reduce the amount of heat that moves through the insulation into the rooms below the ceiling. By the same token, it will also diminish indoor heat losses in the winter.
Although he admits that it might be unnecessary, given that the radiant- barrier sheathing is already in place, Dickerson is considering coating the exterior of the roof with a white-tinted, glass-infused paint called Hyperglass, one of a series of specialized paints marketed under the brand name Hyperseal. A Hyperglass topcoat is filled with tiny hollow glass balls, or microspheres. According to a 2009 article in the Los Angeles Times, the topcoat can deflect up to 85% of the heat that hits a surface; it is layered over a waterproof undercoat made of recycled rubber. Since the town of Thermal experiences approximately 350 days of sunshine a year, this coating would make good sense for the house and the planet. A 2008 study conducted by the Lawrence Berkeley National Laboratory (LBNL) concluded that resurfacing dark roofs with a white material reduces their solar heat gain, lowers their temperature, and directly offsets global warming by transferring heat back into the atmosphere.
Dickerson’s project is subject to all the fits and starts one might expect when relying on donations and a volunteer labor force. For example, whether he will paint all, or simply part, of Torres’s roof white depends on how many solar panels get put up there. As of this writing, a solar company has offered to “solar up” the entire roof for free, but if that doesn’t happen, Dickerson is weighing the advantages of a Solaranda, a solar-shade structure that he would erect on the west side of the house. It would provide much-needed respite from the sun in an attractive patio setting, in addition to providing electricity. In the quest to use less electricity, Dickerson has already installed three Solatube tubular skylights to bring natural light into the darker areas of the home.
This prototype is slightly larger than the layouts planned for the 298 Duroville homes. Those homes will range in size from 1,200 to 1,300 square feet, with three or four bedrooms. Dickerson anticipates costs coming in at well below standard home-building costs, which, in the Thermal area, run about $85 per square foot. Using the ICF building method, he figures he can stack up one new house a day at a cost of about $60,000 per unit. The only item he thinks might increase costs is the up-front expense of solar installation. It all depends on how much he installs and where he installs it. His real savings lie with labor. The project is pending approval for a Workforce Development grant whereby Dickerson will train workers—in many cases idle migrant farmworkers—in green- and sustainable-building methods, and their wages will come from the grant. Local businesses have already contributed well over $100,000, and Dickerson has also applied for a $3.5 million Joe Serna, Jr. Farmworker Housing grant.
Dickerson’s enthusiasm for the project has been noted by the court-appointed receiver for the mobile-home park, and several others have hailed his efforts as the first positive thing to come Duroville’s way in a long time. Building comfortable, efficient, and affordable homes for its hardworking residents, who have essentially been living in squalor, will benefit them as well as the environment.
June Corrigan is a freelance writer from Palm Desert, California.
For more information:
To download a copy of the FEMP report on the Coolerado, go to www1.eere.energy.gov/femp/technologies/newtechnologies_publications.html.
For the article in the Los Angeles Times about the Hyperglass roof reflective coating, go to http://articles.latimes.com/2009/jul/15/business/fi-cool-roof15.
For more on LBNL’s research on cool roofs, go to http://coolcolors.lbl.gov/.
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