An (almost) Air-tight yurt to prevent mold?

[ChrisL]

Hi people

I keep seeing a recuring theme on the forums of mouisture / Mold issues in wet climates.
(I live in UK)
In particular, mold in the

insulation

.

iv been researching a while and have thought of a possible solution, was wondering what you chaps / chapesses thought.

The first yurt i ever stayed in had a vynle cover (that or somthing plastic based, very heavy duty). very watertight.
I get the strong impression that cotton canvas wont suit wet climates.

some suggest making sure the

insulation

is ventelated. But that would reduce its insulation properties.

what if the yurt sat on a plastic ground sheet which folded up the side of the walls a few feet (outside of the wall insuation), with a strip of velcro around the top edge.
The vynle wall cover can then sit on top of that, with a velco strap to connect them.
Then a vynle roof cover which overlaps wall cover and connects them with another velcro strip.

some good rubber seals in door frame would be good.

Asuming all seams are glue'd + sewn properly (+ some tensions straps over all velcro areas) it should give an almost airtight seal on the yurt, and prevent most

moisture

from getting in.
a sealed unit
well thats the theory at least.

perhaps a completely airtight yurt might pose health/safety risk. so maybe a small sliding hatch on front door to let in air (with filter to prevent

moisture

coming through).

what you think?

(i got the idea from a youtube channel 'strateigic living', but the channel gone now :/ )

[Bob Rowlands]

This is out of my field of expertise but I have an opinion about yurts and dampness. Any dwelling made of natural materials is gonna mold in a damp climate. The only way to slow that damp and decay down is through constantly

heating

the building.

Wife and I stayed a night in a friends vacation cabin in Mendocino CA, a very damp climate, that had the furnace shut off for months at a time when there were no occupants. The place was shot through with mold. Never seen anything like it. Mold and damp everyhere, and totally unliveable, the smell was incredible. That furnace could have been on a month prior to our arrival and it hardly would have made a dent in the stink and damp. How tight the place was built would have made no difference at all.

That's just the way it is. It isn't the rain directly coming in, it is the damp air soaking into everything that will absorb it. Wood heat, or a residential style furnace with thermostat set no lower than about 55 is the only solution.

Even Alcatraz, in SF Bay, is returning to the earth and it is basically but concrete and steel for the most part. Moist salt air WILL take out anything that isn't heated and kept up.

My little 16' uninsulated, drafty yurt is in CO, a semi arid environment. Perfect environment for yurts. Even so, the cover is canvas, 3.5 years old and it is covered with mildew spots. The frame is painted, the deck is painted, no issue there at all. Plus, the cover was factory water treated, like Sunforger. But that treatment made it about two years, maybe. It only last so long, it's canvas. Now, the canvas is totally saturated wet in short order when it rains or snows, and THAT is why it was mildewed. Paint the cover is the only solution at this point, and I likely will do that next summer. Or just replace the cover.

That's all I got. And it is just my opinion, I'm certainly no expert on this problem.

[hierony]

I'll also mention that it isn't just about water getting, you need to have a way to drive water out. Humans are quite a large part water, and just breathing adds some moisture to the air. Then there's also all the water we use for living (washing hands, self, dishes; cooking; etc).

You're idea for keep water out of the yurt in the first place is pretty good, I'd say. A pretty high quality groundsheet would be needed, of course. The one I got, I could see little pin pricks of sunlight through it...

Bob's bit about constant

heating

is really kind of the crux of the matter--heat is an excellent way to carry moisture from the inside of a structure to the outside. Otherwise, you'll equilibrate with the outside moisture level.

[Jafo]

Hierony is right. The moisture issues are not from water getting in, it is from water not getting out. Just consider how much water you put in the air when you boil a pot of it.

[Bob Rowlands]

The mass heater hierony is building should mitigate any moisture issues in his unimproved trad yurt. I'd think a mass heater like that would help in a convertional yurt as well. The flywheel effect of heated mass slowly radiating into a building is good design imo.

[hierony]

I'd suspect any heat source that adds heat without adding moisture would work (wood stove, masonry heater, _vented_ propane/natural gas). I am partial to the idea of masonry heaters--we'll see how well it actually works.

[ChrisL]

ah ok, i forgot about the moisture generated from general life stuff.

it sounds like i would need to keep a continuous heat source then.

The Mass heater sounds fascinating, how portable would somthing like that be? as it stands i would be moving the yurt 1 or 2 times a year.

im guessing yurt's aren t great for leaving a few days (holidays, work trip), without a heat source.
what do you guys/gals do if leaving yurt for a few days or more?

do you ask somone to stay and keep fire going?

i asked my boss (construction/carpentry) about a de-humidifier that could be rigged up to solar-pannel system for when im away.
he said they draw a lot of power, and that winter-time solar power would not be enough.

does there exist and kind of lower power de-humidifier that could turn on once a day for a short while?

[hierony]

Well, technically a masonry heater is defined as a fireplace weighing more than 800 kg and with an undamped, high air:fuel ratio (for emission standards exemption in the US). If you can figure out how to move 800+ kg, it's portable :P I'm working on my slave army, or hiring someone with a boom truck when I need to move...

I wouldn't say the place has to be constantly heated. A weekend here and there wouldn't hurt things--except a masonry heater would take a few days to get heating full power again. But going more than a week or so without a good heating/drying out is likely to get mold/mildew started.

[Wintergreen282]

Yes. People add tons of moisture, but if you aren't there breathing, cooking, etc then that is moisture you don't have to "dry off" or vent out. As long as you aren't leaving wet laundry hanging in the yurt as you leave for a rainy week.

I'm sure there are climates you couldn't grow mold in a yurt and climates/yurt set ups (ie # of people, type of cooking, yurts tucked into dark, wet spots) where you couldn't stop mold almost no matter what you did. But moisture is something you can learn about and easily measure. To me, trying to "bend a yurt to your will" (so 1st world probably won't go well. It is what it is. No more, no less. You have to work with it. Maybe that means showering at the gym or outside or sponge baths. Maybe it means the Laundrymat. If that doesn't fit your life, it may not go well. You may get lucky and can do whatever with no mold problems. Or you may have to be super creative.

Of course, then there is the heat issue. Lol. I love my yurt, but there is a fair amount of fussing. Consistency is not what you will get with a yurt. I'll bet right now I could measure a 30 degree difference from the top bunk to the bottom of the side walls. (Often very handy depending on if I want to lay down and read a book or chill a drink! Lol. But not what folks are use to.) Most winter days I go from flannel lined pants and down jacket to shorts and a t-shirt. The yurt's the boss, I just get to live here. Sorry! Way off topic!! Okay. Off to do my exercises before it gets too warm in here.

[silvergramma1]

dehumidifier in yurt,, I once spent a very cold fall in a hennessy hammock when I was homeless,, ( yes I have survival gear) I put foam rubber mattress pad and comforters and bubble wrapped mylar and covered the netting with plastic sheeting and bubble wrap mylar,, still moisture froze on the netting and between the mylar and my foam rubber mattress,, it was worthless.. but I stayed warm,, I shut it down before mold moved into my mattress pad and comforters..
I would use a dehumidifier in the yurt..