I would really like to pick your brain on the other aspects of yurt building too.
Good point about the wool and moisture condensation. I would definitely put good ventilation high on my list for any small living space. I wonder how other natural insulation materials would hold up with that problem?
I do hope I'm allowed to both agree and disagree at the same time.
I wonder if the method you use to process wool isn't the most efficient thus making it seem like a difficult task when it needn't be?
A 5 pound fleece can be washed, picked, carded, and spun in under two weeks - on about an hour a day. I once did two fleeces washed, picked, carded, blended, re-carded, spun and knit in under 10 days, but I had two hours a day to work on it, so it doesn't count. This is all using hand tools, not even a drum carder.
Felting takes a different concentration of effort so we can ignore the spinning and knitting bit. It also doesn't require the fleece be carded - but that does help. Basically, the prep work and time requirements for felting is usually considerably less.
(Orvus isn't perfect however, but that's a topic for another thread).
Once you know the tips and tricks, processing a fleece is fast and easy.
But (a 'but' to negate what I just wrote, not a 'yes...but' intended to negate anyone else) felting for insulation is not one fleece. It is a lot of fleeces.
The fermented wool bath STINKS. There is no nice way to say this. It's part of the process.
For me, the biggest advantage of this process is not using any outside inputs. No soaps or detergents which may be made from ecologically damaging stuff, may or may not biodegrade, and supports the big industrial capitalist complex. What's more, when finished, the liquid from this can be used to fertilize (and possibly deter pests from) your garden. Dilute it at least 10 to one (10 parts water, one part stink juice) or better still 20 or 50 to one.
I tried several methods of rinsing, both hot and cold water.
Please forgive me if this is a completely daft question - is the R value of something for a set thickness or does it change depending on how thick the substance is?
That's amazing about the R value of wool not changing much from batt to felt.
Thinking about yurt and using felt for the walls/insulation...
Wool is (as are many natural insulations) great but it has to "breath freely"...completely free permeability of the thermal diaphragm when used in architecture...no house wraps or related barriers or other condensing surfaces.