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Moisture in the Yurt from Condensation

So if a person heated entirely with wood and had real windows to crack, had no running water (so no showers causing moisture!) but also had no electricity (off-grid means a dehumidifier running 24/7 would be an impossibility) would we ever be able to fend off this terrible condensation issue? I really, really don't want to have frozen domes and yurtcicles.

-30 F days are the norm for our winters.
 
Burning wood really helps with the moisture. I didn't have an issue with moisture and -30 degrees were the norm for us last year too.
 
Well looks like I've just joined the condensation club. For a long time there was no problem, but as temperatures are dropping lately and we have the woodstove lit most of the day, I've just found out there's lot of moisture on the inner side of the roof cover, that's soaking into the hemp felt we have under it. Not sure what to do. Our dome is made as fully closed and we have no windows. Guess we can keep the door open for some longer periods of time during the day, to let the air change. Other than that...I'm not sure. Dehumidifier might be an option. Spending less time in the yurt (less breathing and less heating time needed) would be another. What else?
 
Do you have electric power to your yurt? It might be easier to cut a small hole in your floor and connect a small fan (similar in size & noise to a computer fun) to force a small amount of ventilation outside. The other option might be to let your stove pull a little interior air (the makeup air would then be dry, cold outside air).

Your case puzzles me--all the other reports of yurt condensation have people living full time in the yurt, usually with water facilities and non-breathable covers. I don't recall all the details of your setup though...
 
Yes, we have electric power. The fan might be a way to go, though I think there's some larger caliber solution needed. I was thinking about making several air-pipes of some sorts, that would go somewhere from roof ring along with the rafters and lead outside, under the roof cover skirt. Also, we had the roof skirt tied around tightly, to avoid insect invasion in the summer. Perhaps if I loosen it again, it would allow for both airflow and for some of the moisture to flow out.
We have a gap left over the door, just between the upper door edge and door frame top beam. It has screen to block instect coming to the light and lets some air in/out. The door itself isn't 100% airtight either, as the planks have dried up and that caused many gaps to appear. I planned to fill the gaps and repaint the door, but I guess I'll let it be now. We've moved to the house for a couple days and we let the yurt door open all day to allow as many of the moisture escape as possible, before we decide what to do.
 
Yurts are sensitive to trapped moisture. IMO the cover needs to breathe. If the roof cover is impermeable, then the wall cover should be permeable. Add an operable window?
 
I suspect that when you're getting dew/frost on the ground outside, you'll probably get condensation inside. Any outside air you bring in will have the same dew point, and canvas doesn't insulate much (ie, it'll probably get close to the night time lows causing the dew outside).

I don't know about the weather in your area, but where I'm at in fall we get a fair bit of moisture in the outside air via rain. Our dewpoint is right about freezing, with lows about the same and highs ~40 F/5 C. The only way to prevent condensation this time of year here would be to dry the air inside the yurt (dessicants like zeolite/molecular sieve, calcium chloride, drierite/calcium sulfate; or use a dehumidifier; or outlandishly condensing it out of the air via freezing) and keep the yurt sealed up.

A house has a lot more thermal mass that keeps it warm through the night, plus the walls are usually moderately sealed up (the paint and the plaster/drywall on the interior, paint+wood siding+moisture barriers on the exterior). A yurt, on the other hand, has either fabric lining/insulation/walls which easily let moisture through. So unless the temp of all the yurt's layers is higher than the air's dew point, there'll be condensation.

I think this means either a hot fire all night or a dehumidifier :(
 
I've noticed Mongolian yurts have walls lower than those here in the U.S. Less height, less volume=easier to heat. I understand it is dry in Mongolia, however just possibly the warmer it is inside the less likely condensation can be an issue. Just a guess.
 
Yep, the lower walls would mean less volume to heat and less surface are to loose it through. Mongolians are also a little bit shorter on average and don't seem to think it's terribly important to stand next to your walls with lots of headspace...

From the pictures I've seen and the bits I've read, Mongolian climate is different than most of N. America that I know of, similar though to continental climates (like Colorado). They have cold, dry winters with a little snow and get summer rains (4-15" or such). They get blizzards/zuds some years. Very unlike places with wet, cool springs/autumns.

To use the heating to prevent condensation, you'd have to get the outermost layer above the dew point consistently all night--not terribly easy. I've heard of a fellow that rolls up the yurt skirt a little and bakes the place out with his wood stove after any good fall/spring rains. If you see steam coming off, that's probably hot enough. That'd take some wood, though...
 
You know in all the Mongolian yurts I've seen in photos and videos I don't recall ever seeing a dome or cap. Their smoke holes/rings are covered with a large cloth flap with four attached ropes that drape down so the flap can be pulled over the smoke hole and snugged around the pipe. I don"t believe they have air tight stoves so the stove pipe carries out interior air, let alone the gap that must be left around the single wall pipe if the stove is being used. I'll make guess here and say the air comes in around the door and exits the smoke hole and stove pipe all the time. That absolutely happens in my yurt. Plus it isn't insulated so it doesn't hold the heat at all.
 
I've got layers of insulation throughout my yurt. The outer layer is a 10 mil plastic sheeting. What I've noticed is that condensation collects on that outer layer.

This year, my solution was to put another layer of the same sheeting inside as the inner most layer with blankets between them. Essentially you're creating an airspace between the two plastic sheets which makes the surface of the walls much warmer. As a result, I'm not having moisture collect on that outside wall as I was last year.

I have to believe the moisture is expelling itself through the dome, or the stove pipe. The issues with condensation were pretty extreme last year...so far so good this year though.
 
Kiwassa, that sounds great. I am thinking you are also creating a better heat/moisture barrier for the roof. Less moisture and heat are making it there, leading to less condensation. Great job. Keep us posted how this continues please! :)
 
We live in Big Lake Alaska and it was -13F last week. Last (2014) Thanksgiving is was -29F. We do not have a condensation problem. I have been reading and wondering why. It just dawned on me, that our yurt has Sunbrella fabric as the outside walls. We have a 18 oz vinyl roof. Pella windows and a 4 ft acrylic dome. We heat with wood and oil toyo stove. Standard house door. NO Condensation.
I think the sunbrella Marine fabric breathes. Our insulation is 1/4 inch this solar Guard by BP Solar. The roof has a 1 inch polyester blanket over the Solar guard. (reinforced vinyl, 1/4 inch fiberglas, and layer of pure aluminum)

We have had a problem with the Honda eu300is freezing. I made a blanket of Solar Guard and it now keeps itself warm.
 
Bob Rowlands said:
I've noticed Mongolian yurts have walls lower than those here in the U.S. Less height, less volume=easier to heat. I understand it is dry in Mongolia, however just possibly the warmer it is inside the less likely condensation can be an issue. Just a guess
... You know in all the Mongolian yurts I've seen in photos and videos I don't recall ever seeing a dome or cap. Their smoke holes/rings are covered with a large cloth flap with four attached ropes that drape down so the flap can be pulled over the smoke hole and snugged around the pipe. I don"t believe they have air tight stoves so the stove pipe carries out interior air, let alone the gap that must be left around the single wall pipe if the stove is being used. I'll make guess here and say the air comes in around the door and exits the smoke hole and stove pipe all the time.
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you're right! The more compact shape of the Mongolian ger / yurt means also less surface in contact with the exterior = less surface for condensation and ... less moist air to deal with...
And yes, there's always a bit of air escaping from the toono in Mongolia and the stoves (in which they burn mostly dried animal manure) are far from air tight. Those of our customers who seem the most successful at dealing with moisture... are the ones using their gers just like that :-).
It is also important to underline that traditional yurts in Mongolia are usually between 5 and 6 m diameter (16 to 20') and this is how they are so efficient in their extreme climate.
 
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We live in Northwestern Ontario and have recently moved into a 32’ yurt. We are battling the condensation issue inside. Moisture collects on the inside of the dome, then rains down on us. We heat with propane, so when it gets cold, it’s too expensive to open the dome and let the heat out. We have real windows, but even leaving a couple of them open a bit, doesn’t seem to help. We have put a fan near the peak, have run a de-humidifier and have tried putting bubble wrap up there as insulation. Nothing worked. It continued to “rain” inside the yurt. We don’t plan to live in the yurt most of the winter, but would like to if need be. I was wondering if you think a custom, 2 or 3 pane plexiglass window might help? It would be constructed so that it would be removable, and fit over the dome opening inside the yurt. You said that 2” styrofoam worked, but you lost the light. Would a double or triple pane “window “ insulate as well as the 2” styrofoam? The humidity in the yurt is not very high. I have even put a humidistat up inside the dome, and it isn’t overly high. The windows never have condensation, only the dome, which then rains down onto the furniture, the floor and anyone sitting on the furniture. When you used the styrofoam, was there frost buildup on the dome side of it? Did you leave the dome open a bit once the styrofoam was installed? Are you and your family still living in the yurt? Thanks!
 
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Swykes said:
We live in Northwestern Ontario and have recently moved into a 32’ yurt. We are battling the condensation issue inside. Moisture collects on the inside of the dome, then rains down on us. We heat with propane<snip>
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Burning a 'gallon' of propane produces four gallons of water, so if your propane heater is free-standing, all this will be contributing to your indoor-rainfall problem. Hopefully fluing the exhaust gasses outdoors would make a big difference.
 
I have trimmed a few stick framed houses in the winter over the last few decades that were temporarily being heated with portable propane heaters because the permanent heater wasn't fired up yet. The type I refer to is simple- a large propane tank that has a burner attached to it with a valve and hose. That type heater throttled up to jet engine blast heats a large freezing cold area fast. A 32' yurt at freezing would be toasty warm in just a few minutes.

However, while the heat output is phenomenal, breathing propane combustion gas all day is NOT good, and the moisture produced is incredible. It flat out sucks breathing that air all day. NO WAY I would use that in a permanent residence in fact it would be illegal. A very drafty smaller uninsulated primitive yurt or wall tent with lots of air loss, yes. Just let the unit idle like we do at work and it is not all that bad. Beats freezing your keester.

You definitely need another heater for your yurt. Tight yurts are said to have all kinds of condensation problems, and dumping propane combustion into them would be a fail imo. Dry heat from a good wood stove is good. A regular propane fired forced air furnace that dumps combustion gas outside, would also work. There's a heat exchanger inside so only warm dry air enters the yurt.

fwiw you might find a used one in good condition on Craigslist. Some guys install those in their garages. Good luck.
 
I just remembered, back in the 1970s I used to live in a 20x20 1 bed 1 bath apt. SMALL! It was two areas divided by one wall, each 10x20. A lr/kitchen and 1 bed/bath. Not unlike a 24' partitioned yurt. The heater was a single wall mount furnace in the lr. That worked OK through the winter. The bedroom stayed pretty cold even with the door open, but it was good enough for me. Nowadays I would want another heater on the wall in the bedroom side. So, a wall mount furnace is also a possibility. No ductwork necessary.
 
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