SALIRAJA Yurt Project: Difference between revisions

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Background

CCAT is the Campus Center for Appropriate Technology at Humboldt State University, in Arcata, CA. In_______ CCAT built a yurt to provide a demonstration of traditional nomadic shelter. Traditionally yurts are constructed with canvas roofing. Unfortunately in Humboldt County a yurt is defined by its roof structure and canvas rooftops often don't hold up to the elements. Currently the CCAT yurt has a moldy canvas roof and our goal is to replace it with a water resistant, structurally sound, recycled roof. Recycled materials are a great product for roofing because many materials that are thrown "away" still have the capability to be used as something useful. We are a group of Humboldt State Environmental Science majors, and we are enrolled in Engineering 305 (Appropriate Technology). Our project for the spring 2013 semester is to provide CCAT with a new rooftop for their yurt.

Problem statement

The objective of this project is to creatively utilize recycled materials to create an aesthetically pleasing and technically appropriate yurt roof.

Literature Review

This is a review of some of the available literature on lighting and roofing material pertinent to the yurt re-roofing project at CCAT. The CCAT yurt is a freestanding structure without wiring or electricity. In the past, light was emitted into the building via the white canvas roof. Since that roof has molded it is very dark inside. Because the yurt relies on the roof for light integrating a mold-resistant skylight will be essential.

Roofing Basics

Types Roofing Materials

Aluminum

1. Aluminum cans are light weight, highly reflective, non-toxic, non-pyrophoric, and are easily fabricated. Aluminum also has a high resistance to corrosion due to the invisible oxide skin that forms when it is exposed to the atmosphere.^[1]

Recycled Tires

1. Race slicks have been used to make tire shingles by simply cutting the tires with a razor blade, to the desired shape, and screwing the pieces onto plywood.

Living Roof

Green roofs or living roofs are beneficial not only in their aesthetic appeal but in their environmental benefits of carbon sequestration as well as reflecting more incoming radiation than a traditional roof. Green roofs can actually last longer than traditional roofs, which actually age and reduces in durability when exposed to heat. Bare roofs absorb incoming radiation during the day and increases the temperature, in comparison to a green roof can reduce the temperature of the roof by 45 degrees in some cases. The slope of the yurt roof is suggested to be no steeper than 2:12, which is equivalent to 9.5 degrees, this is what could be the determining factor of any sort of green roof because it is so steep.

1. Moss grows naturally on roofs made of concrete or wood
2. Native forest floor species

Redwood Shingles

Redwood shingles were on the original yurt roof before CCAT was relocated and the yurt was disassembled. The prior shingles are long gone but new shingles could be made.

Lighting

Lighting Concerns

Arcata, Ca is an area which on average has a less than 50% chance of experiencing a sunny day.^[2] This means that a passive solar daylight system must be designed with this in mind. According to Helmut Köster in his book on daylight architecture, it is possible to capture enough light from the sun if the skylights and windows are placed appropriately.^[3] Visual appeal is also important, both on the interior and exterior of the yurt.

Lighting Options

There are several ways to create day lighting that maximize the availability of the sun's light. Solar tubes are a very popular method of natural lighting, and can provide very strong focused light through refraction and reflection of the light via mirrors and lenses inside a tube^[4]. This same (though less dramatic) effect can be created through the use of old plastic water bottles filled with water which is able to refract the sunlight as well^[5][6]. Skylights do not have the same capacity to intensify the sun and capture as much of it, and rely more strongly on clear skies and proper placement, this makes them a less desirable option for the yurt project^[7].

Visuals

If the plastic bottle solar tubes were to be used it would be an added benefit to enhance their visual appeal in the interior of the yurt. Susan Wasinger outlines in her eco-craft book several lamp-shade type projects highlighting creative reuse which would be appropriate, assuming the bottle-bulbs provide enough light.^[8]

Criteria

The following criteria will be used to determine which roofing options will be best suited for this project. The scale is from one (least important) to ten (most important).

Tentative Time Line

References

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