Insulating a yurt roof

[ljamies1]

TKOAK,
I like where your heads at. Im in the process of winterizing my yurt and the ceiling is particularly frustrating to insulate while keeping somewhat portable. Once you begin cutting tapered

insulation

into the rafters relocating would become very frustrating I imagine. What about using heavy duty commercial carpet padding instead of the blanket? You can buy large quantities, many are mold and fire resistent? and im sure by finding the right source or doubling up you could get an R7 value or so. Also, if Bonded logic makes their denim batts wide enough maybe you could patch together a "quilt" from that- very warm (yet pricey)!

[lizsteve]

Hi Folks,
We successfully insulated the roof with salvaged foam board cut to triangles to fit snug in the rafters. Then covered with a muslin for a better look and tacked up with battens. It's great and making a HUGE difference during this very cold winter.
BUT we're starting to notice wet marks on the muslin in the last week or so - and today - it's above 20 degrees for the first time in 2 weeks - condensation is noticeable in dozens of spots on the muslin.

Anybody else experience this and find a solution? Taking down the muslin is a painful thought... We opened the

dome

but I don't know that will really help.

THANKS!

[Reinventor]

That is exactly why we encased our

insulation

in plastic and taped it all down.

[stephanwik]

Originally Posted by lizsteve

BUT we're starting to notice wet marks on the muslin in the last week or so

Normally in Sweden the 'right' way to build is:

- Outer cladding (panels / bricks etc)

- A vapour barrier (Tyvek or similar) to stop the wind but allow

moisture

to escape from the insulation to the exterior.

- Insulation

- a damp proof membrane (often plastic) to stop

moisture

from inside the building migrating into the insulation

- an inner wall

Translating that to a yurt is not totally straightforward, especially since the outer shell is damp proof. However the

dome

does does allow an air flow which we noticed also has a drying effect.

In your case you might want to consider plastic between your muslin and the insulation to stop the humidity from inside the yurt migrating to the insulation. We've also experimented with putting Tyvek between the insulation and the cover, and that has worked well and it minimises condensation collecting in the insulation. The tricky bit is creating enough air gaps to allow any moisture that does accumulate to be transported away however. On the next yurt we'll leave a gap for this purpose by fastening the insulation on the lowest part of the rafter. The insulation itself will not be as thick as the rafter.

I hope this makes sense. The joys of insulating a yurt

[lizsteve]

Reinventor, what you are explaining is :You put the yurt up, then the insulation, then a layer of plastic that you taped the seams?

Now that we have this problem, hindsight is brilliant. I am thinking we should have put Tyvec on the rafters before any insulation. Also could help to wrap the yurt it in too, before the side wall insulation and canvas. Perhaps when this isn't our primary home, we'll take the canvas off and redo it. But sounds like a big job!

We did open the dome a crack yesterday and this morning I don't see the spots on the muslin, so things must have dried a bit.

[Jafo]

Regardless of your solution, I do think it will somehow involve opening to the dome. The moisture has to escape.

[Bob Rowlands]

Cracking the yurt roof vent and/or opening a window or two when cooking or bathing is a good way to get rid of excess atmospheric moisture. Get a natural air flow going and the excess moisture will exit quickly, just as it does in any residential kitchen and bathroom with a window and vent fan.

Canvas and other organic yurt materials need to stay as dry as possible for long life. Damp canvas trapped in long term contact with a moisture laden insulative material is going to be prone to decay. Even in Colorado, canvas tents rolled up damp mildew in short order. It is essential to keep canvas as dry as possible.

[lizsteve]

I've been meaning to follow-up with a photo and I finally properly finished our fabric covering on the insulation which is really just for show. Here's a peek at the finished product (attached I think). Harsh winter - we were glad to have the insulated ceiling. Steve wants to do the walls too, but I am hoping we hold off and rather do real windows that we can open and close from the inside... we'll see. Plus, opening the dome on days 32-40 degrees seems to stop the condensation (at least visually).

[RocktheCasbah]

I would love to see pictures of this! We are thinking of doing the same.

[thebitmaster]

So I consistently see people putting bubble-wrap style radiant barrier insulation in between a decorative inner layer and the outside canvas. Everything I've read says that radiant barrier doesn't work without an air gap on one side. Because of this, I took mine out from between the layers and put it on top, despite the fact that it's not really weatherized for outdoor exposure. The problem is that radiant barrier is an excellent heat conductor, so if things are touching it on both sides the heat conducts right through. This makes it mysterious to me that so many commercial yurts use some kind of bubble wrap insulation *between* layers where it's losing most of its ability to block heat transfer. Does anybody understand the thinking behind doing it that way? I get the idea that you're trying to protect the more fragile radiant barrier from the elements, but that doesn't do any good if there's no air gap.

This is a fairly good explanation of the problem. I think it's slightly oversimplified, because I don't think radiant barrier loses it's ability to block radiant heat with no air gap. It still blocks most radiant heat (nothing has magically changed the aluminum), the problem is that it also conducts conducted heat really well, so if either surface it's touching heats up, that heat goes straight through to the other side.

https://www.radiantbarrierguru.com/n...rrier-to-work/