written by Rene K. Mueller, Copyright (c) 2005, last updated Sat, March 15, 2008
Mon, September 12, 2005: First version
During my research for materials for yurts
I have collected some information, some may be quite specific.
As for the yurt
, it originates from Monogolia, with dry yet very cold and windy environment. When building a yurt in a different climate zone like Europe, or Switzerland to be more specific, more humidity and rain occurs during the wintertime when a yurt is a suitable option for temporary housing.
This is why the traditional felt for the yurt, as example, isn't suitable anymore for the outer layer. I have been searching for alternatives.
So, several layers are considered.
- rain cover
- thermal insulation
The outer layer as I call it must be waterproof, the main function to insulate against rain.
Polyethylen (PE) is one of the options, the blankets are available also up to 30m, at a reasonable price. PE yet isn't fully UV resistant, and may last only 1-2 years at full exposure all year, with colored surface, such as green or blue, the UV resistance is extended to 2-4 years, but much more seems not possible. Aprx. CHF 2-10/m, up to 10m x 12m, or 2.6m x 30m, 180g/2 to 300g/m2
PVC is another option, used for trucks, or quality tents, quite heavy material (600g/m2).
Polyester and Cotton mixture (e.g. 50/50) is quite heavy 300-400g/m2, and suitable for a raincover, but it may require an additional cover to extend its lifetime, e.g. another light cotton layer as in case of a yurt.
The options I have been researching, in regards of suitability and pricing. Additionally material insulation can be measured, thermal conductivity λ, the amount of Watts per Meter per Kelvin, the smaller the value the better the insulation. The k-Value is the actual insulation value for a given thickness of the material:
||λ-Value in W/(m K)k
||k-Value in W/(m2 K) at 10cm thickness
||0.04 - 0.05
||0.4 - 0.5
||20 - 80
||130 - 270
||0.05 - 0.06
||0.5 - 0.6
||160 - 320
||125 - 150
||0.045 - 0.06
||0.45 - 0.6
||15 - 50
||0.03 - 0.04
||0.3 - 0.4
This is the traditional approach, sheep wool processed to felt, at least 5mm thick, thicker the better and heavier and the higher the cost. Aprx. CHF 25.00/m2, 95cm wide.
One of the synthetic alternatives (and less costly) is PE bubble wrap, 1cm thick, and air isolates quite good. Aprx. CHF 1.50/m2, 1.5m wide, quite light material.
Some of the geotextiles are also an option for a cover layer, but unsufficient as whole solution of a temperature insulation.
Cotton isn't a good temperature insolator, but for a spring to fall yurt it might be sufficient. Aprx. CHF 5.00-20.00/m2, 1.5-1.6m wide, 150-200g/m2
For the interior solely aesthetic considerations are important. Cotton or cotton synthetic mixtures are suitable. I personally prefer bright colors, white and bright beige to capture and reflect as much light (e.g. from the roof opening of the yurt). 1.5-1.6m wide lanes.
The floor is required if you build a temporary building in a climate zone which doesn't provide stable and dry ground. E.g. in Monogolia rather dry climate applies to native yurts, and carpets are layed direct unto the grass and ground.
In Europe, where more moist and wet climate is another approach is required. First be aware to find a good location, preferable on top of a slight slope (or even tiny hill) so the (rain) water runs away from you; by no means ever build a temporary building in a land dent, there all water collects.
A wooden floor above gravel is a simple way to get a good floor, but not yet winter suitable.
||Size of particles (in mm)
||60.0 - 20.0
||20.0 - 6.0
||6.0 - 2.0
||2.0 - 0.6
||0.6 - 0.2
||0.2 - 0.06
||0.06 - 0.02
||0.02 - 0.006
||0.006 - 0.002
|Source: British Standards Institution BS 1377, 1975
Prepare the ground first:
- make it even: use sand or straw to make uneven ground even
- insulate against water: choose location on a slight slope or raise
The floor, often multi-layered:
- grid of wood, in which insulation is layed in
- wooden floor
Avoid to use cement for temporary buildings, remain "temporary" even you plan to have it a couple of years.