Our Green Streets Blog

This guest post featuring some information on yurts is written by Bridget Sandorford. Thanks for the post, Bridget.

In the vein of Simon Dale’s low-impact home, yurts have provided countless individuals with safe, earth-friendly shelter for millennia.  Known as üi in Kazakh and ger in Mongolian, yurts are felt-covered, wood lattice-framed, dome-shaped homes of traditional Turkic and Mongolian nomads of the Central Asian steppes.

Historically made from timber acquired in trade and felt from the sheep accompanying the pastoralists, yurts were designed to be built, taken down, and carried on the backs of camels and yaks in as little time as a day.  Something so simply constructed naturally has significantly less impact on the environment than contemporary homes, which is why they’ve been appearing in the western world of late.

Most yurts found in North America today have been modified from the Central Asian üi and ger to be made with steel aircraft cable and architectural fabrics.  We can thank Yurt Foundation founder Bill Coperthwaite for bringing such sustainable living options to the U.S. in the ‘60s and ‘70s, when he built the nation’s first yurt structures as classrooms and studios.  Today, individuals desiring low-impact living call yurts not only their offices but also their homes, vacation or guest houses, and even lodgings for ski resorts and campgrounds.

Moreover, contemporary North American yurts often cost less than a new car (between $5,000 and $20,000) and only take two days and five people to construct once the platform is built.  Because a yurt makes better use of its space than rectilinear homes, it is more efficiently heated and cooled (even in extreme temperatures, thanks to the NASA-developed reflective insulation that reflects radiant heat in both directions).   Despite its simple construction, a yurt’s compression ring and tension band give it surprising strength and support, making it a safe, frugal, and environmentally responsible home, just as the nomads of yore intended.

Since the 1970s, yurts and yurt owners have diversified, and many now consider yurts as their primary homes.  For more information on yurts, check out Yurt Info.

Aside from school and working part-time as an assistant chef, Bridget Sandorford is the resident Culinary Schools blogger where recently she’s been researching culinary colleges in Ohio as well as culinary colleges in Louisiana.

Her passion for food has followed her research into many different areas, such as nutrition, fitness, organic foods, gardening, and cooking on a budget. She lives outside of Charleston, South Carolina.

Use a banking analogy for the untapped and clean geothermal energy our planet provides to find we live on top of a remarkable energy safe deposit vault.

In 2008, geothermal power supplied less than one percent of the world’s energy. However by 2050 it is anticipated that geothermal power will meet between 10 and 20 percent of the world’s energy requirements, notes a report from Renewable Energy World.

Colorado engineer and geothermal innovator Merline Van Dyke says here are many different kinds of geothermal systems, some that rely on hot water from beneath the earth’s surface, others that simply use the constant temperature of soil below the surface as a means of heating and cooling.

“What I’m interested in talking about are the efficient ones,” says Van Dyke. He began experimenting with making homes more efficient in 1994, building a home in the foothills west of Denver, using structural insulated panels.

Van Dyke is presently working with Sims Construction, a Denver builder, as they finish a three-story, 2,400 square-foot geothermal house that uses structural concrete insulated panels (SCIP) on the exterior to maintain efficient temperatures. Net result: R-40 insulation value, an electricity bill that will run half of a normal bill, and no need for natural gas.

The house is located in central Denver and features an Amasond geothermal system. Amasond, an Austrian-based company, provided a geothermal system where pipe was drilled to a non-water level of 118 feet, where the earth temperature was a constant 52 degrees Fahrenheit.  This past summer, Sims flew to Europe to participate in an Amasond training program.

“I am very excited about how efficient this home is going to be,” he says, noting this is the first home of this kind to be built in Denver.

Understanding Geothermal Basics

Geothermal energy – or heat from the Earth – has been used in a variety of ways since the early annals of human life on this planet. Perhaps best, in this day and age, most geothermal energy is clean and sustainable, depending on what procedures are used. Hydraulic fracturing of rock below the surface, a procedure used in oil and natural gas capture, is being explored as a way to obtain hot water, but the environmental impacts to this procedure are being questioned by some. Resources of geothermal energy range from the shallow ground to hot water and hot rock found a few miles beneath the Earth’s surface, and down even deeper to the extremely high temperatures of molten rock called magma.

A geothermal heat pump system consists of a heat pump, an air delivery system (ductwork), and a system of pipes buried in the ground near the building (see photo). In the winter, the heat pump removes heat from the heat exchanger and pumps it into the indoor air delivery system. In the summer, the process is reversed, and the heat pump moves heat from the indoor air into the heat exchanger. The heat removed from the indoor air during the summer can also be used to provide a free source of hot water.

The Department of Energy, working with the National Renewable Energy Lab (NREL) in Golden, CO undertakes ongoing research to develop and advance technologies for various geothermal applications.

Geothermal heat pumps use much less energy than conventional heating systems, since they draw heat from the ground. They are also more efficient when cooling your home. Not only does this save energy and money, it reduces air pollution. The GEO Exchange http://www.geoexchange.org/ is a trade association for geothermal heat pumps, an integral part of any geothermal system.

In modern direct-use systems, a well is drilled into a geothermal reservoir to provide a steady stream of hot water. The water is brought up through the well, and a mechanical system – piping, a heat exchanger, and controls – delivers the heat directly for its intended use. A disposal system then either injects the cooled water underground or disposes of it on the surface.

Geothermal Electricity

In 1911, the world’s first geothermal power plant had a capacity of 250 kilowatts. By 1975 the Larderello fields were capable of producing 405 megawatts of power. It was the world’s only industrial producer of geothermal electricity until 1958, when New Zealand built a plant in Wairakei. The Geysers Resort Hotel, California, was the site of the first geothermal power plant in the United States. The Geysers currently produces over 750 Megawatts of power annually.

Today, 69 geothermal power facilities are in operation at 18 sites around the United States, and geothermal power is generated in over 20 countries around the world.

Once a finely constructed house or building hid the vast majority of its inner parts. Like the skin on a body, drywall, plaster, or some other curtain was constructed to conceal a complex web of plumbing pipes and joints, electrical wiring and outlets, and a crisscross of ductwork used to feed heating, air conditioning and ventilation runs. And don’t forget the structural members – the 2×4s or steel beams that held the whole works together.

Such concealment is not always the case today. The ceiling components in many new stores and restaurants – once discreetly hidden by a drop-ceiling grid containing 2’ x 4’ panels – now reveal a run of girders, PVC pipes and smartly painted ductwork for the HVAC system.

Colorado Architect Doug Eichelberger says his first memory of encountering exposed infrastructure was the Pompidou Center in Paris, named after then president, Georges Pompidou. Opened in 1977, the center is famous for its structure. Its distinctive architecture depicts all of the air ducts, water pipes, electrical lines, etc. on the outside of the building. It is an interesting example of visual mapping.

Each building could be mapped with its pipes and electrical lines that are usually hidden within the walls. The Pompidou Center shows all of these lines and pipes painted in different colors so that one can distinguish them; the air ducts are painted blue, water ducts are green, electricity lines are yellow and staircase and elevators are red.

As the center’s flyer clearly states: “The building’s structure is turned completely “inside out” and even the steel beams that hold the construction together are visible on the outside.”

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Gabion baskets, traditionally used for building retaining wall and controlling erosion, also can be used as a homebuilding product for emergency settlements or by those wishing to construct walls with new material approaches.

Colorado architect Doug Eichelberger has used gabion baskets to construct an experimental building on his ranch southwest of Larkspur, CO that he now uses as attractive free-standing barn. But he is most interested in the potential use of gabions where natural or human-caused disasters have occurred and there is a critical need for emergency housing.

As Eichelberger writes: “In war and natural disaster situations, emergency housing is one of the first requirements in the lives of survivor/refugee population. Gabion baskets are most often used for erosion control along rivers and streams. The baskets can also be used in a vertical wall structure. Because the baskets are easy to transport and assemble, they can be taken (even by mule) to the most remote locations. The baskets can be filled with rubble from destroyed buildings, then left as is or covered with indigenous mud stucco finishes. The baskets can be arranged into homes or refugee barracks.

Eichelberger says these are features to this structure:

• Baskets can be filled with stone or concrete rubble
• Baskets are easy to transport to remote locations, where they can be filled with material of choice
• Weight of filled baskets makes for stable floating foundation
• Inexpensive materials are used for fill

A couple of places worth visiting for gabions are GabionBaskets.net and Maccaferri.  Maccaferri, based in Williamsport, MD is a pioneer company in gabions, constructing its first wire basket in 1893.

According to Maccaferri, the first gabion retaining structure was constructed in 1893 to retain the banks of the River Reno at Casalecchio. It took 650 workers, 34 days to install the 2,900 gabions.

Gabion retaining structures are rectangular wire mesh baskets that are usually (concrete rubble, in some cases) filled with rock at the project site to form flexible, permeable structures such as gabion retaining walls for commercial, industrial and road projects. They are also used for erosion control for bank stabilization, channel linings, and gabion weirs.

Gabion strength lies in its double twisted hexagonal mesh of steel wire which is reinforced by selvedges of heavier wire running along the edges and by transverse diaphragms. The wire will not unravel even when cut. Assembly is easy, requiring no specialized labor and nearby rock is used for fill.

Gabion retaining structures are available with different levels of protecting coating for durability. With 30% voids, gabion structures offer free drainage providing greater bank stability when used for riverbank protection.

Modular homes or pre-manufactured kits may be appealing because of lower costs and the speed with which the final product can be assembled, but what differences do they have when it comes to measuring green qualities?

On the positive side of the green scale, a few basics stand out: first, because of off-site manufacture of all wall and structural components, very little waste is created, especially when compared to a traditional stick-built home where it is common to fill five to seven 40-yard (8’ x 22’ x 8’) construction dumpsters that haul leftover debris to nearby landfills. Leftovers at the factory are usually recycled, or put to some other use in the finished home.

Second, the majority of prefabricated homes prove to be more energy efficient. Because they have been manufactured in a factory, this involves insulation and HVAC considerations. Manufactured homes commonly have insulation with R-values — the higher the number, the better the insulation — of 21 in the roof, 11 in the side walls and floor.

Most pre-manufactured homes come with Energy Star rated appliances and heating systems.  Energy Star homes are often 20 to 30 percent more efficient than traditional homes. In addition, low “E” window packages help contribute to a tighter building envelope.

Third, indoor environmental air quality is considered before putting together the entire package.

Genesis Homes, this nation’s largest modular homebuilder, believes in strict adherence to a green standard.  “As the Nation’s largest modular builder, we have chosen to adhere to the National Association of Home Builders (NAHB) Green Standard. This standard provides you with third-party certification that the modular home you are purchasing can deliver on its claims of energy efficiency and resource conservation.”

Are there any negative considerations regarding the green perspective? Maybe only the amount of fuel required to deliver the unit to its final destination. But in a traditional stick-built home, even more petroleum is required for the many materials deliveries for all subcontractors involved – carpenters, roofers, insulation, HVAC, electric, etc.

As the world and its urban areas grow more congested and material supplies wane, modular homes and kits appear to be options that deserve serious exploration.

Whether to build a home from a modular package or from a kit involves both cost, design, and ease of assembly considerations.

Since most of the components for modular homes are built offsite – including interior and exterior finishes, the primary onsite design factors involve foundation, water, sewage and how the structure will be powered. Kits will require a considerable labor investment.

A standard modular home package that is shipped by road can measure anywhere from a 300 square foot cabin to a two-story home. Wardcraft Homes, based in Clay Center, KS, and with other plants in Minden, NE and Fort Morgan, CO, ships a standard pre-manufactured unit or box, measuring 15’ x 60’. Martin Schneider, a project manger, says two such units, when married together at the final destination, will provide a three-bedroom, two-bath, ranch home.

All Wardcraft modular packages are shipped with exterior and interior finishes, including, lighting, plumbing and HVAC. Unlike one predecessor to modular homes — the trailer – there are many attractive design options.

“If you’re comparing stick-built to modular homes, there’s not much difference in cost,” says Schneider. “The savings you’ll find is the efficiency and the quality (factory, computer-controlled manufacturing).”

He adds there is also a lower cost on construction financing, due to the quicker assembly turnaround. Stick-built construction financing is generally planned for 12 to 18 months. Modular home construction normally runs 180 days.

Aside from modular options, there are also pre-manufactured kits. A Tilton, NH-based company, Shelter-Kit, has been shipping ready-to-assemble home and barn packages for over 40 years.

The company sells a number of small size custom post and beam barns, sheds and buildings. Shelter-Kit president, Dave Kimball believes his company provides its customers with substantial benefits over the average pre-built shed sold at many big-box home and garden retailers.  The choices in small buildings are versatile, both aesthetically and functionally.

The company’s first product – the Unit One cabin, a 12’x12’ structure – is still sold and has even been made into a backyard office. Other customers have purchased additional units so the can add on to the original structure. This kit is priced at $10,700.

Today, Shelter-Kit’s customizable barn-style buildings start with a compact 16’x 16’ and are available in larger sizes, up to 36’ wide. They are created individually for each customer with high quality wood materials and hardware (of substantially better quality than what is found in most “standard” sheds). Most kits include roofs but no HVAC, plumbing, or electrical packages.

Shelter-Kit products are designed to be buttoned up quickly and easily – they can be assembled by only two people in 3 -15 days, depending upon the size of the structure.

’The Do-it-Yourself’ nature of our product allows customers significant cost savings, but with the ability to maintain exceptional quality,” says Kimball.  “There are no added expenses of contractors and builders, plus since all of our products are manufactured at our facility, there is significantly less waste.”

Next, we will report on green considerations about modular’s and kits.

For anyone that has ever worked with a Lego set, it is easy to understand the appeal of modular thinking. Consistency and interchangeability immediately come to mind.

According to Jetson Green, the business today of off-site fabricated homes – shipped as modules, kits or panels – is robust.  Preston, Jetson Green chief editor, writes that prefabrication offers “several potential benefits that the housing industry cannot ignore: accelerated construction, controlled construction, construction without the elements, and minimal waste.”

Many of these modular homes are now being marketed under a green heading. For instance, last year, Nationwide Homes launched the eco-cottage (see photo on next page). Ranging in size from 300 to almost 600 square feet, the eco-cottage might be used for “a separate sleeping quarters or hobby space for your arts & crafts or even an office space,” writes Nationwide.

There are many reasons for the appeal of prefabricated homes: cost, less waste, factory precision, ease of construction and energy efficiency representing a few of the basic considerations. In addition, there is the real or perceived “green factor.”

According to Modular Homes, “Green modular homes are now being built that allow people to live comfortably without using as many natural resources.”

Of interest, a majority of these modular homes have been designed considerably smaller than traditional American homes.

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There is more than one way to create a tall building that can provide dwellers with access to the outdoor air or a garden, even if it happens to be on the 10^th floor.

A high-rise building concept called the stairscraper was recently featured on the gizmag website. This design innovative skyscraper design comes from Barcelona-based firm Nabito Architects. With one of the best-known drawbacks to high-rise living being the lack of outdoor space, this firm solves the problem by using a corkscrew design that makes the roof of the unit below an outdoor space for the unit above.

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TSC Global, championing its innovative “Roofs for the World” program, met in Denver with a group of earth building advocates, including Partners Worldwide and Iowa-based Vermeer Tractors for a full production test run of the Vermeer’s mobile compressed earth block machine press.

Brad Wells, TSC executive director, says Vermeer drove its equipment from Iowa, setting up a mobile production facility to manufacture over 1000 compressed earth blocks (CEBs) which TSC will then use to complete the walls on a demonstration unit at its Denver headquarters. Wells believes this represents a new building paradigm for impoverished areas in the world.

The CEBs were manufactured on facilities west of Denver that had been donated by Church Ranch, where the team used “a mountain of blue ribbon dirt!” says Wells. The goal of this endeavor is to build durable, inexpensive structures that will resemble the Ugandan units developed by Moses Musaazi Kampala, as shown in this photo.

This October, a group of international business people gathered to observe Vermeer’s portable CEB press – the 714 Dynabloc Press. Vermeer and Faith Tech Connect developed the machine to use in worldwide poverty areas to build low-cost CEB homes and provide jobs to local residents in the process.  The blocks are produced using a mixture of clay-based soil and a small amount of cement for bonding.

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Those wishing to have the best natural light for interior spaces may want to take a look at Sunflower Corporation and its Sundolier^®, a lighting system designed to deliver high quality indirect daylight to large spaces.

The line of “daylighting” products developed at the Boulder, CO-based Sunflower Corporation are designed with this objective: to provide sustainable natural lighting that meets the high quality lighting demands of education, office, retail and industrial markets.

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