Yurt purists will insist adamantly that its simply is not a true yurt if it has solid walls. Yet, the original yurts, from Turkey to the Himalayas, had neither tarpaulin skins or space-age bubble insulation and glass-domed vents. Yurts, indeed, are more about simplicity and function than any purist concept of how they should be designed, and from what materials.
It is true that the lattice/tarpaulin skin systems employed by manufacturers from Yurtco to Colorado Yurts have aesthetic appeal. Their flexible framing, bubble insulation and heavy-duty pvc tarps allow for an intimacy with the surrounding environment that a conventional house or cabin does not. The sound of rain on the exterior skins is magical, and the thick plastic windows create an aura of living in a tent. Even in relatively stiff winds, these yurts hold steady, yet react to the breezes. Yet, these same benefits also can be drawbacks.
Since windows are nothing more than thick, clear poly plastic, they transmit heat and cold easily. To cut down on sun infiltration, the exterior skin must be zipped shut. Similarly, in winter, those same windows almost always are zipped closed, creating a claustrophobic, tomb-like atmosphere. If the window is improperly installed and allowed to vibrate or shake, the plastic quickly breaks down, and, in a matter of a few years, the window must be replaced when it cracks.
The light lattice framing does withstand winds of 70-90 kph, but a wind/snow load supplementary support system must be installed in high wind/high snow regions. Of particular concern for many is the loose fit of the yurt wall skins at the base of these units. While tight enough to hold back the elements, many yurts with lattice wall design, according to owners, allow small rodents such as voles to work their way into the building during the colder months.
Due to the thinness of the exterior walls, R-factor levels for insulation are minimal, with only a few centimetres of space-age bubble insulation protecting against the elements.
A reasonable fear that some people have expressed is that the light construction is a poor impediment to a hungry bear, who may smell food through the fragile skeleton of the yurt. Whether the fear has ever materialized is irrelevant, as the fear may still exist even where the risk is minimal.
On the other hand, solid-wall yurts offer a great many advantages. Few bears, badgers or raccoons have the tenacity to force their way through 7/16 inch of wood, plus framing, making the structure seem considerably safer from these predators than flexible-wall yurts.
With the exterior tarpaulin covering those walls, wind and air infiltration is minimal. The framing allows for two to three times the insulative capacity than lattice walls.
Wind endurance is significantly greater in a properly designed solid wall yurt, as well. Using the interlocking top and bottom plate segments that has been created for these units, the structures have endured winds of over 115kph, without any sign of stress or strain. In one instance, a healthy tree, sixteen inches in diameter, was sheared off by the wind not more than forty yards from the yurt, yet the yurt suffered absolutely no ill effects from the wind force.
Window and door installation is easier and less expensive in solid wall yurts. Because of their framing, these buildings can be constructed using standard windows (double or triple pane) and doors, allowing for reduced cost, energy saving and better light infiltration. It is also a lot more difficult for a raccoon to claw through a pvc & glass window than a plastic one!
Along with the advantages of solid wall construction, these hybrid yurts maintain the tarpaulin roof structure, along with added truss strength to withstand heavier snow loads. The tarpaulin skin allows for the same magical enjoyment of a rainfall on the tent-like roof, the same intimacy with the outside environment and the same open atmosphere as more “traditional” yurt systems.
Yurt purists may decry the bastardization of their beloved structures, but they will have a hard time denying the advantages of solid-wall over flexible-wall yurts.
Friday, June 17, 2011
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