30' yurt + insulation layering

[Aaron Harris]

I have a 30' yurt on a 2-by T&G platform with a dry bermed, insulated, heated walk-in "crawlspace" basement with barrels of water as a thermal mass. (So I'm not insulating the floor).

I opted not to pay $3400 for reflective bubblewrap in a liner.

I think my solution will be building 'pie pieces' out of the following.

I can get the reflective bubblewrap for about $500.
I can get 1/8" of wool felt for about $800 per layer.
I can get 1/4" wool felt for about $1600 per layer.
possible white tarp or other vapor barrier?
natural cotton muslin on hand for inner wall appearance

I could supplement with foam panels between other layers.

Now, Air gaps are a good thing, so I think 2 x 1/8" will (always?) be better than 1 x 1/4" and I know I want to control for condensation, perhaps using the reflective as a vapor barrier.

Which layers would you include in what order? I'd like to keep the cost under $2500

Any particular overlapping strategy between roof and walls other than the roof felt outside wall felt, except for vapor barrier that wants to ceiling to weep inside wall... ?

Thank you so much!
AH

PS I want to thank hierony and others for their pointing me to wool products and felt.

[Corinarose]

I live in a 30' yurt in Vermont. So winters are cold. The reflectix

insulation

is not useful or helpful in any capacity IMHO. I have it but it was not worth it, so you have done well by not purchasing it.
I spent about $900 putting 6" of roxul

insulation

in my walls and ceiling.
The down fall is the frost that accumulates on the inside of the outer layer
(no reflectix did not act as a vapor barrier).
This year I will add a vapour barrier about the insulation and the outer layer.

If I had to do it all over again I would choose the permancy of a wooden yurt

best of luck
Corina

ps i have lived in my yurt 5 winters.

[Aaron Harris]

Thanks, Corinarose. I had not thought of anything like roxul. That sounds like a great solution if paired with an interior vapor barrier. Is your lattice exposed? Are your snow supports exposed? Are your roof rafters/poles exposed?

I'm trying to understand - is your reflextix outside or inside the roxul? If it's outside, I wouldn't expect it to act as a vapor barrier - warm air from inside makes its way through the insulation and condenses its water on the coldest thing (outer layer) where you get frost... if there's a gap at the bottom of the reflectix, I can see the warming suck moist air in the bottom and up the wall.

AH

[hierony]

I've been pondering the moisture/humidity thing some. I'm not sure if there's a 'perfect' solution, especially as a lot depends on your particular yurt setup and climate.

I've heard from a fellow in a traditional yurt in a somewhat rainy climate--he basically baked out the yurt if it stayed wet for too long (ran his wood stove hot until the outer layer started steaming).

With a modern yurt, general venting and targeted venting of source areas (enclosed bathroom, nearby sinks, etc) will likely take care of most issues. Again, monitor the humidity and figure out the dewpoint and compare to the outside temp--if the outside temp is at/below dewpoint, watch out for condensation. If you notice condensation, give it airflow and some heat and ventilate to get the

moisture

outside. The only time this wouldn't work is if there's a water leak (from outside, from a pipe, etc).

For insulation order, I'm not yet convinced it's terribly important yet. If you have a natural canvas cover, a breathable

moisture

barrier immediately under the canvas would prevent any leaks from soaking inwards while allowing a little vapor outwards. If you don't have a natural canvas cover, a second moisture barrier may or may not be useful.

Roxul might be a good fit for your situation. My traditional yurt gets moved too frequently for it to work well though--it is a slightly crumbly and probably wouldn't handle more than one or two moves. Being mineral, it shouldn't be a food source for mold if it does get a little wet.

[Pixiemoss]

Originally Posted by Corinarose

I live in a 30' yurt in Vermont. So winters are cold. The reflectix insulation is not useful or helpful in any capacity IMHO. I have it but it was not worth it, so you have done well by not purchasing it.
I spent about $900 putting 6" of roxul insulation in my walls and ceiling.
The down fall is the frost that accumulates on the inside of the outer layer
(no reflectix did not act as a vapor barrier).
This year I will add a vapour barrier about the insulation and the outer layer.

If I had to do it all over again I would choose the permancy of a wooden yurt

best of luck
Corina

ps i have lived in my yurt 5 winters.

We are thinking of doing rockwool between our snow and wind kit studs in our yurt. Then cover with paneling.

Did you do a vapor barrier with this and is it still working out ??

Thank for any feedback

[froit1]

the technology is simple, kids:
First the vapor barrier in the inside, then the insulation, then a venting space on top/outside of that, and then your waterproofing.
Because of the difficulty to achieve the venting-space in layers which rest om each other, you need a moisture-open, waterproof outer layer. Home-wrap can do that, but it is usually ugly, not meant for regular folding and travelling, and not very UV nor wind-proof.
Hence to add an outer cover, which is water-and moisture-open, but wind- and UV-proof.
Which material would that be????
Flag-polyester.