Saturday, December 1, 2018

How to Build a Yurt


How to Build a Yurt.
Yurts are simple and quick to build compared to other alternative homes. The traditional Mongolian yurt is brilliant in its simplicity. Physics rather than brawn provide structural strength. The lattice wall leans slightly out, a steel cable holds it in place enabling the wall to support the roof. The drawbacks are: poor ventilation, no windows and perhaps having to cuddle up to sheep for supplemental heat. These can be easily rectified by framing in windows, installing an airtight woodstove and fitting fiberglass insulation into the earth plaster covering the wall frame. A two-foot roof overhang, along with a coat of lime wash protects the wall from rain.  A cedar log in the center supports the roof. The bones of the building are Mongolian, the skin is Iron Age Celtic. The timeless challenge is to turn the dream into reality when you’re clinging to the margins of society. There is also the spectre of building permits and bye-law regulations. These are there to protect us from our own and our neighbour’s follies and misfortunes. Building codes are based upon what has pasted the test of time. Imagine Monty Python as a Roman building inspector facing down the Mongol horde of Genghis Khan… “Yurts?!!!... Nooooooo…  you must have proper buildings.” Building an alternative home is a Homeric journey – you can make it to the distant shore with sweat, research and a smidgeon of luck.
Kindness, helpfulness and sociability are all marketable skills. Baby boomers are now in their dotage and many elderly people are living alone on beautiful rural properties. Some of them would welcome the comfort and security of having a supportive couple living close by. Local government is edging in this direction. To help this trend we need to build things right.
There is a long list of parameters to consider when choosing a site. Southern exposure, protection from prevailing wind, avoiding low ground, water management and vehicular access to name a few. This is going to be your home, make it so magical that you never want to leave. Luckily, creativeness and frugality go hand in hand. There is a bibliography at the end of these notes, these books will give you the knowledge and confidence you need. Take comfort with the thought that these building techniques and materials have proven successful for thousands of years, unlike the modern suburban home which is experimental and decidedly dodgy to live in with off-gassing, flammable materials and stale air. Before going into the details of construction it helps to have an overview so that you can have a picture in your mind’s eye.
The yurt is built on a two-foot high platform of packed sub-soil with a top-dressing of limestone screenings. In my experience, a twenty-foot diameter starter home with a 315 sq. ft. floor is the right balance between economy, structural strength and liveability.  The rounded door is framed by fitting two curved logs together, the window frames are attached to posts dug into the ground. The lattice wall is covered on the inside and outside with an earth plaster, fiberglass insulation is sandwiched between the plaster. The chimney for the woodstove passes through the wall. Three of the five window open and this ensures good cross-ventilation. The cedar poles for the lattice wall are seven long and five inches in diameter. The poles for the roof are twelve long and six inches diameter at the top. The roof poles are two feet apart at the wall. Roof strapping is done with salvaged 1” by 6” planks. Three layers of tarps cover the roof, the middle one is 100% waterproof, the other two protect it from the rough edges of the planks and from UV radiation. The roof is covered with a thin layer of compost; this holds down the tarps, helps to insulate and looks natural.
All houses need to be higher than the surrounding land to protect them from surface run-off.  Building on packed sub-soil rather than on a timber frame prevents having cold air and critters under the floor. The platform needs to be at least six feet wider than the yurt. Driving over the dirt with a front-end loader tractor as it is being built will pack it hard. Then, add a top dressing of six inches or more of limestone screenings. Wet screenings packs hard.
Before building the wall, the center post needs to be set in position along with posts for the door frame and the main south-facing window. The posts for the other windows are smaller and they are fitted after the wall is up. The trick to digging holes by hand in hard ground is to use water. Dig as deep as you can be using a digging bar, spade and digging clams. When you hit impossibly hard ground pour six inches of water in the hole, twenty minutes later the ground will be soft enough to get down another few inches, repeat this until you reach a depth of at least 2’9”, preferably 3’6”. I’m fortunate to have cedar logs available which are resistant to rot. An alternative method is to place the post in a plastic bin to protect the wood from moisture.
Curved and irregular shaped doors and windows have charm and character. Hanging the door and fitting the two curved door posts takes ingenuity and chainsaw skills. I scout my woodlot for a pair of curved logs at least eight feet long and no less than eight inches in diameter. These are dug into the ground on the east side to form an arch. The door is roughly four feet wide and five feet high, big enough for furniture and a full-size mattress to fit through. The trick is to have enough of one door post plumb so that the door doesn’t open like a gull’s wing. The door opens outward so that bears at least knock before entering. Next, set a pair of 8” posts on the south side to frame the window, measure the width of the window and allow for the 2” by 6” planks that will frame it. It is easier to frame the window if the posts are half-rounds.
A 20’diamerter circle has a circumference of just over 62ft. My yurt has 32 roof poles, each one is supported at the wall by the crossed wall poles. The first step is to make about thirty pairs of crossed poles. The dimensions are: 7’ poles that are five to six inches in diameter, crossed 9” from the top with the base 52” apart. Fasten them together with 6” or 8” nails. Mark the position of the wall by laying a rope on the ground. Place the first pair of crossed poles in position on the line of the wall and support them temporally with a 12’ roof beam. Add the next pair of crossed poles so that the tops are two feet apart. Follow the same pattern with the remainder of the wall poles, for example, the right leg of one pair cross over and in front of the left leg of the next pair. This maintains the curvature of the circle. After a few pairs are in place, only every third or forth with need to be supported. Lean the wall poles out approximately five degrees. Thread 3/8” steel cable through the joins of the poles and attach the ends with a turnbuckle. Adjust the poles so that you now have a uniform lattice wall that leans slightly out. Tighten the turnbuckle. Wire the legs of the poles tightly together wherever they cross. The roof poles can now be placed in position to form the roof frame. The thin end of the poles rest on the wall. The roof overhang above the south window may need to be adjusted to maximize the heat, winter sunshine and sprouting salad greens.
Iron Age round houses had a roof angle of 14 degrees. Steep enough so that rain flows off, but not so steep that it becomes a torrent eroding the platform or the living roof. The inside height is eight feet in the center and six feet at the wall. The center post supports over thirty poles with seven-inch tops. Ideally, find a tree trunk that has a fork or large limb that can be used to support some of the poles. Alternatively, fit four poles on the trunk and lay the others on top of these. Anchor the poles with eight-inch nails. The roof is then covered with 1” by 6” planks, preferably hardwood. Fit the planks close together, otherwise the tarp can bulge through the gap. Dumpster cowboys are center stage during roofing when scrap timber and trashed tarps are golden. There are many options for the waterproof layer. A heavy-duty agricultural tarp costs about $400 and polythene vapor barrier $40. Then there are all the hi-tech liners used for tailing ponds. My choice was polythene vapor barrier sandwiched between old worn tarps and this works fine. The vapor barrier comes in eight-foot widths and is taped in position. Fasten the edge of the tarps to the underside of the roof overhang. A wood frame of light poles holds the tarps and the ‘black gold’ compost in place. Take a pair of seven-foot poles (left over from the wall), attached the ends together six feet apart with wire, place this over the peak of the roof, do the same with another pair of poles in the opposite direction. The peak should now be ringed by four poles approximately three feet from the top of the roof. Attach more poles onto these until there is a spider’s web of poles covering the roof. This ‘deadman’ style of construction enables a fabric to be anchored to a roof without punching nail holes in it. Next, shovel a three-inch layer of compost onto the roof.
Windows provide ventilation, heat in winter and year-long daylight. It is easiest to fit standard recycled windows. If you have the time and ingenuity, rounded plate glass table tops, car windshields or even a car door can be fitted into the wall. I drive pick-up trucks until they drop, the doors are reincarnated into hobbit homes. There is something about winding down the window, feeling the fresh summer breeze, tunes taking you down memory lane and you’re still on the couch. The main south-facing window is a full-size glass patio door set sideways. Three other windows are timber-framed and have hinges on the upper side, so they swing open from the top. They are framed into posts dug into the ground, the frame must be sturdy enough to support a section of the roof because one pair of wall poles is removed to fit the window.   A smaller window on the west side allows the late afternoon sun to stream in. Quality of life inside the yurt is dependant upon good ventilation, plenty of daylight and scenic views.
The lattice wall is covered with fabric and chicken wire, this will later be covered with earth plaster. An alternative is to weave branches or lathes between the poles to hold the plaster. Landscape fabric provides a cheap breathable barrier, house wrap is a more expensive option. The fabric provides a layer between the plaster and the fiberglass insulation.  The wall has five layers: a lime white wash, earth plaster, chicken wire, fabric, fiberglass insulation, fabric, chicken wire and earth plaster. The fabric and chicken wire are nailed to the lattice wall. Thread 12-gauge wire through the chicken wire to give it extra support. The fiberglass insulation is fitted into the lattice wall. The result is a weather proof breathable wall at minimal cost. Planet loyalty, aesthetics and breathability is why you should use earth plaster and not cement stucco.
The floor is paving stone or interlocking brick. These are easy to embed into the limestone screenings. Master scavengers can source these from the detritus of construction projects. The stone floor is a heat sink for sunshine and the woodstove. A wood floor and area carpets can be added later. A small airtight wood stove provides heat and is used for cooking. The chimney passes through the wall where it is protected from the weather by the roof overhang. Anchor the chimney to the roof for support. Read the building code before installing the stove.
A 40-watt solar panel with a charge controller and a 12- volt battery will power LED lights and charge a smart phone or tablet. Ideally, have two batteries so that there is backup for overcast winter days. The cost jumps substantially if you add more panels and an inverter for AC current. In practice, it’s cheaper to have a top- quality generator for when you need more power, such as, running a vacuum cleaner or a vehicle block heater. Generators must be run regularly to remain reliable.
Earth plastering is where you really connect with the planet - mixing sand, clay and water together, squishing straw into it and then massaging gobs of it into the wall. It takes time, ingredients can be varied, mistakes can be rectified, and the results are deeply satisfying. It’s more important to grasp the principles and variables than rigidly follow a recipe or technique. First, do a simple test to learn the percentage of the ingredients in the proposed earth you plan to make the plaster out of. Half fill a jam jar with dirt, fill it water add a spoonful of salt and shake. Sand, silt and clay will separate out enabling you modify the mix so that you have roughly a 50-70% sand to clay mix. Earth plaster is clay, sand, fiber and water mixed so that it’s soft and sticky. Adapt what you’ve got to what you need. Here is an overview; clay is the glue, sand gives strength and reduces shrinkage and straw reinforces. It’s best to have three layers, the first gives a rough layer that is pushed into the wire mesh to form a strong base. The second layer smooths out the unevenness and the final layer is finer, thinner and less likely to crack. It can take a week or more for each layer to dry. To help the second and third layers stick, wet the plaster with a lime wash. Longer straw is stronger than short. Plastering is unleashing your creative genius; it takes you off on wild riffs improvising with shredded paper, animal manure, hair, sawdust – the list is endless. Mastery comes practice or to borrow a line from Van Morrison - ‘you have to do it for real, anytime, anywhere’.
Barefoot Architect by Johan Lengen                                     Copyright 2018, Hugh Morshead                                                                                          Earthbag Building by Kaki Hunter and Donald Kiffmeyer                                                           Building Green by Clarke Snell and Tim Callahan
How to Build a Yurt.
Yurts are simple and quick to build compared to other alternative homes. The traditional Mongolian yurt is brilliant in its simplicity. Physics rather than brawn provide structural strength. The lattice wall leans slightly out, a steel cable holds it in place enabling the wall to support the roof. The drawbacks are: poor ventilation, no windows and perhaps having to cuddle up to sheep for supplemental heat. These can be easily rectified by framing in windows, installing an airtight woodstove and fitting fiberglass insulation into the earth plaster covering the wall frame. A two-foot roof overhang, along with a coat of lime wash protects the wall from rain.  A cedar log in the center supports the roof. The bones of the building are Mongolian, the skin is Iron Age Celtic. The timeless challenge is to turn the dream into reality when you’re clinging to the margins of society. There is also the spectre of building permits and bye-law regulations. These are there to protect us from our own and our neighbour’s follies and misfortunes. Building codes are based upon what has pasted the test of time. Imagine Monty Python as a Roman building inspector facing down the Mongol horde of Genghis Khan… “Yurts?!!!... Nooooooo…  you must have proper buildings.” Building an alternative home is a Homeric journey – you can make it to the distant shore with sweat, research and a smidgeon of luck.
Kindness, helpfulness and sociability are all marketable skills. Baby boomers are now in their dotage and many elderly people are living alone on beautiful rural properties. Some of them would welcome the comfort and security of having a supportive couple living close by. Local government is edging in this direction. To help this trend we need to build things right.
There is a long list of parameters to consider when choosing a site. Southern exposure, protection from prevailing wind, avoiding low ground, water management and vehicular access to name a few. This is going to be your home, make it so magical that you never want to leave. Luckily, creativeness and frugality go hand in hand. There is a bibliography at the end of these notes, these books will give you the knowledge and confidence you need. Take comfort with the thought that these building techniques and materials have proven successful for thousands of years, unlike the modern suburban home which is experimental and decidedly dodgy to live in with off-gassing, flammable materials and stale air. Before going into the details of construction it helps to have an overview so that you can have a picture in your mind’s eye.
The yurt is built on a two-foot high platform of packed sub-soil with a top-dressing of limestone screenings. In my experience, a twenty-foot diameter starter home with a 315 sq. ft. floor is the right balance between economy, structural strength and liveability.  The rounded door is framed by fitting two curved logs together, the window frames are attached to posts dug into the ground. The lattice wall is covered on the inside and outside with an earth plaster, fiberglass insulation is sandwiched between the plaster. The chimney for the woodstove passes through the wall. Three of the five window open and this ensures good cross-ventilation. The cedar poles for the lattice wall are seven long and five inches in diameter. The poles for the roof are twelve long and six inches diameter at the top. The roof poles are two feet apart at the wall. Roof strapping is done with salvaged 1” by 6” planks. Three layers of tarps cover the roof, the middle one is 100% waterproof, the other two protect it from the rough edges of the planks and from UV radiation. The roof is covered with a thin layer of compost; this holds down the tarps, helps to insulate and looks natural.
All houses need to be higher than the surrounding land to protect them from surface run-off.  Building on packed sub-soil rather than on a timber frame prevents having cold air and critters under the floor. The platform needs to be at least six feet wider than the yurt. Driving over the dirt with a front-end loader tractor as it is being built will pack it hard. Then, add a top dressing of six inches or more of limestone screenings. Wet screenings packs hard.
Before building the wall, the center post needs to be set in position along with posts for the door frame and the main south-facing window. The posts for the other windows are smaller and they are fitted after the wall is up. The trick to digging holes by hand in hard ground is to use water. Dig as deep as you can be using a digging bar, spade and digging clams. When you hit impossibly hard ground pour six inches of water in the hole, twenty minutes later the ground will be soft enough to get down another few inches, repeat this until you reach a depth of at least 2’9”, preferably 3’6”. I’m fortunate to have cedar logs available which are resistant to rot. An alternative method is to place the post in a plastic bin to protect the wood from moisture.
Curved and irregular shaped doors and windows have charm and character. Hanging the door and fitting the two curved door posts takes ingenuity and chainsaw skills. I scout my woodlot for a pair of curved logs at least eight feet long and no less than eight inches in diameter. These are dug into the ground on the east side to form an arch. The door is roughly four feet wide and five feet high, big enough for furniture and a full-size mattress to fit through. The trick is to have enough of one door post plumb so that the door doesn’t open like a gull’s wing. The door opens outward so that bears at least knock before entering. Next, set a pair of 8” posts on the south side to frame the window, measure the width of the window and allow for the 2” by 6” planks that will frame it. It is easier to frame the window if the posts are half-rounds.
A 20’diamerter circle has a circumference of just over 62ft. My yurt has 32 roof poles, each one is supported at the wall by the crossed wall poles. The first step is to make about thirty pairs of crossed poles. The dimensions are: 7’ poles that are five to six inches in diameter, crossed 9” from the top with the base 52” apart. Fasten them together with 6” or 8” nails. Mark the position of the wall by laying a rope on the ground. Place the first pair of crossed poles in position on the line of the wall and support them temporally with a 12’ roof beam. Add the next pair of crossed poles so that the tops are two feet apart. Follow the same pattern with the remainder of the wall poles, for example, the right leg of one pair cross over and in front of the left leg of the next pair. This maintains the curvature of the circle. After a few pairs are in place, only every third or forth with need to be supported. Lean the wall poles out approximately five degrees. Thread 3/8” steel cable through the joins of the poles and attach the ends with a turnbuckle. Adjust the poles so that you now have a uniform lattice wall that leans slightly out. Tighten the turnbuckle. Wire the legs of the poles tightly together wherever they cross. The roof poles can now be placed in position to form the roof frame. The thin end of the poles rest on the wall. The roof overhang above the south window may need to be adjusted to maximize the heat, winter sunshine and sprouting salad greens.
Iron Age round houses had a roof angle of 14 degrees. Steep enough so that rain flows off, but not so steep that it becomes a torrent eroding the platform or the living roof. The inside height is eight feet in the center and six feet at the wall. The center post supports over thirty poles with seven-inch tops. Ideally, find a tree trunk that has a fork or large limb that can be used to support some of the poles. Alternatively, fit four poles on the trunk and lay the others on top of these. Anchor the poles with eight-inch nails. The roof is then covered with 1” by 6” planks, preferably hardwood. Fit the planks close together, otherwise the tarp can bulge through the gap. Dumpster cowboys are center stage during roofing when scrap timber and trashed tarps are golden. There are many options for the waterproof layer. A heavy-duty agricultural tarp costs about $400 and polythene vapor barrier $40. Then there are all the hi-tech liners used for tailing ponds. My choice was polythene vapor barrier sandwiched between old worn tarps and this works fine. The vapor barrier comes in eight-foot widths and is taped in position. Fasten the edge of the tarps to the underside of the roof overhang. A wood frame of light poles holds the tarps and the ‘black gold’ compost in place. Take a pair of seven-foot poles (left over from the wall), attached the ends together six feet apart with wire, place this over the peak of the roof, do the same with another pair of poles in the opposite direction. The peak should now be ringed by four poles approximately three feet from the top of the roof. Attach more poles onto these until there is a spider’s web of poles covering the roof. This ‘deadman’ style of construction enables a fabric to be anchored to a roof without punching nail holes in it. Next, shovel a three-inch layer of compost onto the roof.
Windows provide ventilation, heat in winter and year-long daylight. It is easiest to fit standard recycled windows. If you have the time and ingenuity, rounded plate glass table tops, car windshields or even a car door can be fitted into the wall. I drive pick-up trucks until they drop, the doors are reincarnated into hobbit homes. There is something about winding down the window, feeling the fresh summer breeze, tunes taking you down memory lane and you’re still on the couch. The main south-facing window is a full-size glass patio door set sideways. Three other windows are timber-framed and have hinges on the upper side, so they swing open from the top. They are framed into posts dug into the ground, the frame must be sturdy enough to support a section of the roof because one pair of wall poles is removed to fit the window.   A smaller window on the west side allows the late afternoon sun to stream in. Quality of life inside the yurt is dependant upon good ventilation, plenty of daylight and scenic views.
The lattice wall is covered with fabric and chicken wire, this will later be covered with earth plaster. An alternative is to weave branches or lathes between the poles to hold the plaster. Landscape fabric provides a cheap breathable barrier, house wrap is a more expensive option. The fabric provides a layer between the plaster and the fiberglass insulation.  The wall has five layers: a lime white wash, earth plaster, chicken wire, fabric, fiberglass insulation, fabric, chicken wire and earth plaster. The fabric and chicken wire are nailed to the lattice wall. Thread 12-gauge wire through the chicken wire to give it extra support. The fiberglass insulation is fitted into the lattice wall. The result is a weather proof breathable wall at minimal cost. Planet loyalty, aesthetics and breathability is why you should use earth plaster and not cement stucco.
The floor is paving stone or interlocking brick. These are easy to embed into the limestone screenings. Master scavengers can source these from the detritus of construction projects. The stone floor is a heat sink for sunshine and the woodstove. A wood floor and area carpets can be added later. A small airtight wood stove provides heat and is used for cooking. The chimney passes through the wall where it is protected from the weather by the roof overhang. Anchor the chimney to the roof for support. Read the building code before installing the stove.
A 40-watt solar panel with a charge controller and a 12- volt battery will power LED lights and charge a smart phone or tablet. Ideally, have two batteries so that there is backup for overcast winter days. The cost jumps substantially if you add more panels and an inverter for AC current. In practice, it’s cheaper to have a top- quality generator for when you need more power, such as, running a vacuum cleaner or a vehicle block heater. Generators must be run regularly to remain reliable.
Earth plastering is where you really connect with the planet - mixing sand, clay and water together, squishing straw into it and then massaging gobs of it into the wall. It takes time, ingredients can be varied, mistakes can be rectified, and the results are deeply satisfying. It’s more important to grasp the principles and variables than rigidly follow a recipe or technique. First, do a simple test to learn the percentage of the ingredients in the proposed earth you plan to make the plaster out of. Half fill a jam jar with dirt, fill it water add a spoonful of salt and shake. Sand, silt and clay will separate out enabling you modify the mix so that you have roughly a 50-70% sand to clay mix. Earth plaster is clay, sand, fiber and water mixed so that it’s soft and sticky. Adapt what you’ve got to what you need. Here is an overview; clay is the glue, sand gives strength and reduces shrinkage and straw reinforces. It’s best to have three layers, the first gives a rough layer that is pushed into the wire mesh to form a strong base. The second layer smooths out the unevenness and the final layer is finer, thinner and less likely to crack. It can take a week or more for each layer to dry. To help the second and third layers stick, wet the plaster with a lime wash. Longer straw is stronger than short. Plastering is unleashing your creative genius; it takes you off on wild riffs improvising with shredded paper, animal manure, hair, sawdust – the list is endless. Mastery comes practice or to borrow a line from Van Morrison - ‘you have to do it for real, anytime, anywhere’.
Barefoot Architect by Johan Lengen                                     Copyright 2018, Hugh Morshead                                                                                          Earthbag Building by Kaki Hunter and Donald Kiffmeyer                                                           Building Green by Clarke Snell and Tim Callahan

No comments:

Post a Comment