Sheep wool insulation and how many sq ft of wall space?

[kidjedi]

Originally Posted by A W Warn

One byproduct of burning polyisocyanurate foam insulation is hydrogen cyanide gas. It is poisonous, deadly to humans. That is the main reason it is hardly ever used in residential construction.
https://www.firehouse.com/rescue/art...ong-fire-gases

FWIW, it would be pretty difficult to get it burning in the small cavity between outer and inner (metal) Airstream skins.


As far as "hardly ever used in residential construction..." I'm not sure where those stats would come from, as it is widely used in residential and commercial construction and has arguably the best R value per cubic inch available until you get into super expensive materials like aerogel.

[Tony Lee]

Mineral rockwool is hydrophobic unlike fibreglass and natural wool which once they get wet, stay wet for weeks.

[kidjedi]

The conversation regarding Thinsulate now has me thinking...


They also make a product called TAI3027 that is 21mm thick. I wonder how that product compresses. Currently I use rolled polystyrene (the blue stuff for house construction sill plates) as a thermal barrier on the ribs (between the ribs and interior skin), but if the TAI3027 would work there, I could see gluing the SM600L to the cavity side of the exterior skin, and then gluing the TAI3027 across the entire cavity side of the interior skin before riveting to the ribs. Thus, there would be a single sheet over the entire interior skin. That would make for a nice continuous seal of the cavity, while also tackling the thermal barrier issue at the ribs.


I would also like to do some experiments on the Thinsulate, similar to the experiments I did with Polyisocyanurate (to see just how hydrophobic it actually is).


Finally, I am curious as to the 248 degree F rating of the SM600L. I have taken temperature readings of the exterior skins that have registered well in excess of 300 degrees. I know that's not an every day kind of thing, but it definitely happens (especially here in Colorado), so I would want to make sure that this stuff doesn't melt, especially when glued to exterior skins, on a hot sunny day!

[Starstream]

As a natural fiber lover (knitter & hand spinner), it might seem kind of strange to hear me say “I wouldn’t recommend wool insulation.” There are at least a couple of reasons I can mention.

One – a sheep’s natural water proofing comes from lanolin. Which is greasy & stinky. That’s why it’s usually removed when the fiber is processed for yarns & fabric. Two – there are many different breeds of sheep, living in different environments & their fiber qualities can vary quite a bit. Which does affect the end product. I’m pretty certain sheep wool insulation is felted rather than woven. Because it’s for a product which is being stuffed between walls, it’s not going to have the highest quality fibers in it. Instead it will be the stuff which is too short or poor quality for other processing. Wool without its lanolin can soak up water like a sponge, is heavy when wet & can take a couple of days to dry out. That’s when it’s exposed to open air. Commercial sheep wool insulation is treated with Borax? I don’t consider Borax an inert mineral. I use it as a bleach alternative in some of my laundry.

You don’t have to take the opinions of anyone on this forum as gospel, however. Sometimes just reading isn’t enough. This is something you can actually test before using it, which I would strongly recommend. Especially if you live in a damp or humid environment. Order a sample piece of insulation & get some 100% wool felt from a fabric store. (Look for it on the internet if your local brick & mortar doesn’t carry it). Make sure both pieces are the same size, place them outside in the weather for a few days, then give them both a squeeze into separate containers to see how much water each contains. You could also lay the insulation on a piece of aluminum to see if there will be any corrosion issues with the borax. It goes without saying that this experiment will only be accurate if you know what alloy was used in your trailer’s skin & can find the same thing for testing. (Check with Andy from Inland RV. Give him your trailer’s VIN & he can probably tell you what to look for.) Make sure you do a stress test too. Try pulling the insulation apart. It may take many tries, but you will want to know at what point it fails. Sheep wool is a champion felting fiber. However, you’re looking at putting it in something with all those flexing seams, which will be stressed if you plan to travel with it. It’s all those seams, especially on older vintage AS, which would make me cautious about using an insulation popular with van conversions. They aren’t an apple-to-apple comparison.

PS – Love the puns. The only thing which might trump a good pun is a highly creative limerick.

[kidjedi]

Originally Posted by Starstream

PS – Love the puns. The only thing which might trump a good pun is a highly creative limerick.

MCPC was wond'ring if sheep's hair
Could keep an Airstream warm in cool air
A question was asked
And opinions were passed
But no definitive answer was found there.

[tallytwo1994]

Originally Posted by MCPC

It’s treated with borax from what I’ve seen. I know one person who also has their own sheep plan on this:
“...my plan is to wash the fleeces of dirt and suint but leave the lanolin for its water repeling ability. I don't want it collecting all the condensation from the aluminum shell. For moths I plan to add cedar, clove and cinnamon to the walls. For typical bugs that plague all homes, I will add a dish of borax between the studs.”

And here’s an article about the company that uses it. https://moderncampermag.com/sheeps-w...er-eco-camper/

From what I’ve read it is no longer treated with borax but is treated with
Thorlan IW. You can read about that on this page: https://eco-buildingproducts.com/pro...v=7516fd43adaa

For the person who asked about vans... that use the product see this: https://eco-buildingproducts.com/spr...v=7516fd43adaa

Now for this issue of wool, moisture retention, and what appears to be a misunderstanding of natural wool products containing lanolin. I won’t discuss this at length because it would take too long to explain my practical experiance with natural wool. However a perfect example of the absorbing yet dry to the touch qualities of wool can be found in the world of wool diaper covers. Yes, I’m talking about nappies. More than a dozen years ago, mothers who didn’t want to continue the practice of contributing disposable diapers to the landfill, and also wanted an alternative to plastic covers, revived a very old practice of using knitted and crocheted natural wool diaper covers over cloth diapers. The wool absorbs any urine that escapes the cloth diaper, yet you don’t feel any dampness unless the lanolin has been completely washed out. The diaper cover, called a woolie, then dries out on its own without leaking to outside clothing. Obviously the wet diaper is changed to keep the baby dry. After washing the woolie several times the mother re-lanolizes the cover, and the cycle is repeated.

Based upon an understanding of the qualities of wool, and my personal experiance with natural wool, I wouldn’t hesitate to use it as insulation in an Airstream or any other dwelling.

Carol

[MCPC]

Originally Posted by tallytwo1994

From what I’ve read it is no longer treated with borax but is treated with

Thorlan IW. You can read about that on this page: https://eco-buildingproducts.com/pro...v=7516fd43adaa



For the person who asked about vans... that use the product see this: https://eco-buildingproducts.com/spr...v=7516fd43adaa



Now for this issue of wool, moisture retention, and what appears to be a misunderstanding of natural wool products containing lanolin. I won’t discuss this at length because it would take too long to explain my practical experiance with natural wool. However a perfect example of the absorbing yet dry to the touch qualities of wool can be found in the world of wool diaper covers. Yes, I’m talking about nappies. More than a dozen years ago, mothers who didn’t want to continue the practice of contributing disposable diapers to the landfill, and also wanted an alternative to plastic covers, revived a very old practice of using knitted and crocheted natural wool diaper covers over cloth diapers. The wool absorbs any urine that escapes the cloth diaper, yet you don’t feel any dampness unless the lanolin has been completely washed out. The diaper cover, called a woolie, then dries out on its own without leaking to outside clothing. Obviously the wet diaper is changed to keep the baby dry. After washing the woolie several times the mother re-lanolizes the cover, and the cycle is repeated.



Based upon an understanding of the qualities of wool, and my personal experiance with natural wool, I wouldn’t hesitate to use it as insulation in an Airstream or any other dwelling.



Carol

Thanks. I had seen some videos from that company too. I also have tried woolies with my son so definitely had that in mind as well. Though I gave up on them bc it was too hard to pull over his butt lol!

[kidjedi]

Originally Posted by tallytwo1994

The wool absorbs any urine that escapes the cloth diaper

This sounds bad to me for insulation inside an Airstream wall. I realize the wool wouldn't be absorbing *urine,* per se, but if it's absorbing other stuff and can't be cleaned (because it's encased in an aluminum wall)... that sounds like a problem 10 years down the road.

[Starstream]

MCPC was wond'ring if sheep's hair
Could keep an Airstream warm in cool air
A question was asked
And opinions were passed
But no definitive answer was found there.

Well done, kidjedi, well done…

On the wonderous qualities of wool, I’m not necessarily disagreeing. I’ve been knitting for more than 30 yrs. Spinning is a more recent endeavor & I own 2 English Angora rabbits to support my habits. I will admit Angora is my favorite fiber, followed by Alpaca. (Someone on this forum received an Alpaca/Angora hat & scarf from me. I’ll leave it up to them to weigh in on the insulating qualities of those fibers.) I still like sheep wool, too. Have some wool sweaters I’ve owned for more than 20 yrs. & still wear them when it does get cold enough in Texas. If you want to look at historical precedent, animal fibers have been protecting humankind from the elements for eons. Especially in harsh, cold environments. Since I’m usually going to spend weeks or months working on a project, I’ll reach for “natural” fibers whenever possible. I certainly won’t blend anything with the Angora wool, that my rabbits and I work so hard to produce, with anything I don’t feel is an equivalent quality. My choices are also dictated by the parameters I’ve set for a particular project and it’s intended long-term use.

Quite frankly, if I was going to use an animal fiber as in insulation in our AS, I would felt my waste Angora wool into fabric sheets. (I’m a firm believer in “Waste not, want not.) It’s 8 times warmer than sheep wool, lighter in weight & holds air so aggressively between the fibers, it’s difficult to get it wet. Does that mean I consider it a practical choice as insulation? Eh, not necessarily. Yes, Angora is classified as a luxury fiber, which wouldn’t exactly stop me. Ask my husband & he’ll tell you I’m the queen of impracticality. (There is a difference of opinion on that one.) It’s the hands-on experience which forms my opinion here. While I think Angora wool is fabulous stuff, I’ve fussed with it enough to understand its limitations too. I also wouldn’t need to work so hard to use it as insulation in our trailer anyway. In fact, I could achieve this goal by doing no work whatsoever. Besides the 2 EAs, I also have 2 Lionhead bunnies & we have 3 dogs. All of them travel with us. All I have to do is ignore the housekeeping. Viola! Free natural fiber insulation.

The bottom line? Sometimes there just isn’t any substitute for figuring out things out for yourself. Try/test things, make objective observations of facts, then form your own darn opinions! This is especially true of anything you want to use where it’s never been applied before. It appears no one else here has actually used sheep wool insulation in their AS. I think it’s been established the best anyone can offer is an opinion based on experiences that may, or may not, apply. I’m guessing the OP only wants to install insulation in their project once. So take the time to put it to the test before spending lots resources on it. While you’re at it, get samples of the other insulation products suggested in this thread & do side-by-side comparisons. That’s really the best way to decide what’s going to suit your expectations. Ideals are great & they can help make us better as a species. But here’s the sad truth. Sometimes it’s best to make a compromise & life is full of them. How are you going to know when you need to make such a decision? By taking the time to do some hands-on research every once in a while. As many here already know, you will not find 100% consensus on any topic anywhere on this forum. Besides, where is the personal satisfaction in being a sheeple? (Hey, if you happen to be a home-schooling parent, get the kids involved in this process. Determine your scientific/testing parameters & turn it into an assignment. Bonus! You’re getting a 2fer.)

Keep this in mind as well. What defines a natural product? Remember asbestos? It’s a natural insulator too. One that turned out to be highly toxic & should have been left in the dirt where it belongs. Something those who discovered it should have taken the time to figure out, before rushing it into industries & peoples’ homes. If they did know, that makes its use down-right criminal. Corporations have a history of creating/selling questionable merchandise. They’re quite convincing with their marketing when trying to sell their stuff to the rest of us. The only way to truly know if something meets your standards, is to be involved with it throughout the entire production process. Is that the modern definition of practical? Uh, no. How do you combat such sneaky behavior? Re-read the above paragraph. It’s also a good idea to maintain healthy levels of open-mindedness & skepticism.

MCPC, don’t be afraid to be the first person to try something. Taking the time to truly learn & understand is never a wasted endeavor, even when you don’t get the results you expected. If you do decide to use sheep wool insulation in your trailer, please come back to this thread in a couple of years and provide an honest review of its performance. I’m pretty certain there will be at least a few enquiring minds who will want to know. Mine included.

[tallytwo1994]

Originally Posted by MCPC

Thanks. I had seen some videos from that company too. I also have tried woolies with my son so definitely had that in mind as well. Though I gave up on them bc it was too hard to pull over his butt lol!

Sounds like a management issue to me. Children grow, they need larger clothes. ��
Carol

[MCPC]

Originally Posted by tallytwo1994

Sounds like a management issue to me. Children grow, they need larger clothes. ��
Carol

He was still a newborn. They fit, but I didn’t like the wiggling I had to do. Preferred my snaps or Velcro, especially at 2am when I’d usually be using them lol.

[MCPC]

Originally Posted by Starstream

Well done, kidjedi, well done…



On the wonderous qualities of wool, I’m not necessarily disagreeing. I’ve been knitting for more than 30 yrs. Spinning is a more recent endeavor & I own 2 English Angora rabbits to support my habits. I will admit Angora is my favorite fiber, followed by Alpaca. (Someone on this forum received an Alpaca/Angora hat & scarf from me. I’ll leave it up to them to weigh in on the insulating qualities of those fibers.) I still like sheep wool, too. Have some wool sweaters I’ve owned for more than 20 yrs. & still wear them when it does get cold enough in Texas. If you want to look at historical precedent, animal fibers have been protecting humankind from the elements for eons. Especially in harsh, cold environments. Since I’m usually going to spend weeks or months working on a project, I’ll reach for “natural” fibers whenever possible. I certainly won’t blend anything with the Angora wool, that my rabbits and I work so hard to produce, with anything I don’t feel is an equivalent quality. My choices are also dictated by the parameters I’ve set for a particular project and it’s intended long-term use.



Quite frankly, if I was going to use an animal fiber as in insulation in our AS, I would felt my waste Angora wool into fabric sheets. (I’m a firm believer in “Waste not, want not.) It’s 8 times warmer than sheep wool, lighter in weight & holds air so aggressively between the fibers, it’s difficult to get it wet. Does that mean I consider it a practical choice as insulation? Eh, not necessarily. Yes, Angora is classified as a luxury fiber, which wouldn’t exactly stop me. Ask my husband & he’ll tell you I’m the queen of impracticality. (There is a difference of opinion on that one.) It’s the hands-on experience which forms my opinion here. While I think Angora wool is fabulous stuff, I’ve fussed with it enough to understand its limitations too. I also wouldn’t need to work so hard to use it as insulation in our trailer anyway. In fact, I could achieve this goal by doing no work whatsoever. Besides the 2 EAs, I also have 2 Lionhead bunnies & we have 3 dogs. All of them travel with us. All I have to do is ignore the housekeeping. Viola! Free natural fiber insulation.



The bottom line? Sometimes there just isn’t any substitute for figuring out things out for yourself. Try/test things, make objective observations of facts, then form your own darn opinions! This is especially true of anything you want to use where it’s never been applied before. It appears no one else here has actually used sheep wool insulation in their AS. I think it’s been established the best anyone can offer is an opinion based on experiences that may, or may not, apply. I’m guessing the OP only wants to install insulation in their project once. So take the time to put it to the test before spending lots resources on it. While you’re at it, get samples of the other insulation products suggested in this thread & do side-by-side comparisons. That’s really the best way to decide what’s going to suit your expectations. Ideals are great & they can help make us better as a species. But here’s the sad truth. Sometimes it’s best to make a compromise & life is full of them. How are you going to know when you need to make such a decision? By taking the time to do some hands-on research every once in a while. As many here already know, you will not find 100% consensus on any topic anywhere on this forum. Besides, where is the personal satisfaction in being a sheeple? (Hey, if you happen to be a home-schooling parent, get the kids involved in this process. Determine your scientific/testing parameters & turn it into an assignment. Bonus! You’re getting a 2fer.)



Keep this in mind as well. What defines a natural product? Remember asbestos? It’s a natural insulator too. One that turned out to be highly toxic & should have been left in the dirt where it belongs. Something those who discovered it should have taken the time to figure out, before rushing it into industries & peoples’ homes. If they did know, that makes its use down-right criminal. Corporations have a history of creating/selling questionable merchandise. They’re quite convincing with their marketing when trying to sell their stuff to the rest of us. The only way to truly know if something meets your standards, is to be involved with it throughout the entire production process. Is that the modern definition of practical? Uh, no. How do you combat such sneaky behavior? Re-read the above paragraph. It’s also a good idea to maintain healthy levels of open-mindedness & skepticism.



MCPC, don’t be afraid to be the first person to try something. Taking the time to truly learn & understand is never a wasted endeavor, even when you don’t get the results you expected. If you do decide to use sheep wool insulation in your trailer, please come back to this thread in a couple of years and provide an honest review of its performance. I’m pretty certain there will be at least a few enquiring minds who will want to know. Mine included.

Thanks. Will still think on it and consider how we could test it. I do know wool has been used in other countries for a long time so I’m not so worried about it being a new fad. It’s just new to our country lol.

[Starstream]

Scientific experiments always start with questions. Ideal conditions are the baselines. Worst case scenarios are where you will find your answers. It sounds like you have specific requirements for the insulation you ultimately use. Those are your questions. Get ugly & abuse any product you test. (Great stress reliever in case the spouse or kids have annoyed you.) Find different ways to destroy your samples, which mimics damage that can occur in your trailer. Just don’t forget to keep safety first. Especially if you decide to set something on fire.

Here are some questions to get you started.

How thick is the sheep wool insulation? Is it similar to a fiberglass bat? Or less than 1/2"? If it's not thick enough to fill the space the between the outer & inner shells, how will you keep it in place? Is the insulation stiff enough to support itself? Does it attract static electricity like a stocking cap or wool sweater? (Static could be bad. Airstreams need to flex, therefore they are constructed in a “few” segments. There will be friction when the trailer is moving & aluminum does conduct electricity.)

This might be the best way to set up a waterproofing test:

One piece of insulation & one piece 100% wool felt fabric. It will be a volume test. Make sure your test pieces are the same weight. Record the weights. (They may not be exactly the same physical dimensions, since the insulation will probably be thicker.) The felt fabric is your baseline because it probably doesn’t have the waterproofing additive. Submerge both pieces in water for 24 hrs. Use something heavy, which doesn’t float, to keep the samples submerged. At the end of the soaking process re-weigh the samples & compare the new data with the original data. The insulation may stay completely dry during the initial test. To test for failure? Keep submerging the insulation & re-checking its weight. For how long? A week might do it. After all, insulation completely submerged in water is the worst case scenario.

[Hein]

If you go ahead with some experimental testing, Please allow me to send a sample of 3M Thinsulate(TM) SM600L in order to compare results.


All the best,
Hein

[MCPC]

Thanks. We won’t be back till the summer. I’ll try to remember then.

[girasoledonn]

Hey there! A year after this post was made, I too came across sheeps wool from this site and am considering it for insulating my trailer. I was wondering if you chose to go with sheeps wool, and if you could tell me how it went. https://havelockwool.com/fiberglass-...ol-insulation/

[ROBERT CROSS]

Originally Posted by kidjedi

Wool settles (compacts) over time, and also absorbs moisture. I know it will dry out (if you live in a desert climate ), but these two factors eliminated it as a choice for me.



Polyisocyanurate panels or industrial (not canned) closed-cell spray foam is what I decided were best after a LOT of research.


FWIW, a couple years ago I submerged a bunch of pieces of PIC in water and I've been pulling them out over time (the experiment is still going). That stuff is nearly impervious to moisture (though it will *burn* in an open environment).

Moisture would be the best argument against the trapping of sheep wool between two sheets of aluminum.
Even the rare unit without any external leaks has condensation...sheep can run around the pasture to dry, and my Filson will keep me warm even when soaking wet and dries nicely in the open air.
And wool does smell funny when it gets wet.
Trapped in an AS not ideal.

Bob
🇺🇸

[girasoledonn]

Originally Posted by ROBERT CROSS

Moisture would be the best argument against the trapping of sheep wool between two sheets of aluminum.
Even the rare unit without any external leaks has condensation...sheep can run around the pasture to dry, and my Filson will keep me warm even when soaking wet and dries nicely in the open air.
And wool does smell funny when it gets wet.
Trapped in an AS not ideal.

Bob
🇺🇸

Talked to the guys at Havelock Sheeps Wool in New Zealand and asked them a zillion questions. Thought their response might be interesting to add to the thread.

We take the opportunity to educate and promote the science of wool fibers.

literally google: the science of the wool fiber. https://www.sciencelearn.org.nz/reso...bre-properties Read a bit there and then read below.

SETTLING OVER TIME???
We produce a batt that is a specific density and we stitch it together with its own fibers. Wool fibers resist settling as the millions of fibers are constantly moving while absorbing and disrobing moisture. As long as you fill the cavity depth with the correct thickness of batt, it will stand up forever (and without batteries).

ATTRACTS INSECTS???
Our raw material is cleaned to certain specifications. Clean wool is paramount to having a legitimate and certified building product. Don't forget our real market is high end building, building science and high performance structures. Boric Acid is quite an effective and long term deterrent for bugs and moths. Again, we insulate thousands of attics and crawl spaces- no issues. Carpenter ants love foam board by the way.

BORIC ACID CORROSIVE??
Again, we are specified for home building and in wall systems builders use alloy fasteners and metal studs. I fail to understand how corrosion happens in the absence of prolonged moisture. Wool manages moisture. This is a huge advantage as you already know by reading through the science of the wool fiber from above. I don't want to sound redundant but when wool absorbs moisture a chemical reaction takes place that creates heat and movement (won't settle) and wool is still dry to the touch (so is the airstream wall).

P.S - Fiberglass insulation is the worst offender for harboring moisture, I guess cotton insulation would be a runner up as it too is hydrophilic. Dunk a piece of fiberglass in a glass of water. Dump the water out and let me know when it is dry. Try the same with wool.

DOES WOOL GET AND SMELL FUNKY WHEN WET?
Sheeps wool will not allow for mold growth; it is a keratin and again is hygroscopic, it creates heat, moves to resist settling and dries out quickly. There are no moldy sheep for a reason.

WOOL CAN DECOMPOSE IN A YEAR IN A LANDFILL??
yes in a landfill. Not in a van, home, airstream or the Edinburgh castle. Sheeps wool is the oldest insulation on the planet and will outlast the structure it is used in.

A MOISTURE BARRIER NEEDED??
a moisture barrier would be a poor choice. First, wool excels in high moisture areas - like an airstream or van. Second, vapor barriers end up trapping moisture on the wrong side anyways because they fail. Vapor drive is inherent.

[ROBERT CROSS]

Well, I guess it's time for you to try it. it

I still question wet,(insert any fabric), between two sheets of aluminum.



Bob
🇺🇸

[Hein]

3M Thinsulate SM600L is the only Acoustic/Thermal insulation specifically engineered for vehicles. It passes all FMVSS requirements and is used by automotive manufactures like Honda, GM, Ford and even Tesla.

It has been installed in 1000s of vans with excellent results and exceedingly high customer satisfaction. It is about 1/2 the weight of wool, contains no borates, and doesn't have any smell what-so-ever when dry or wet. The fibers are hydrophobic so will not absorb or swell with moisture.

Please reach out to Kim@DIYvan.com for a free sample. It makes sense to evaluate Thinsulate before committing to something else which may not be as good. The SM600L is 1.75" to 2" thick so absolutely perfect for insulating an Airstream. I used Thinsulate to replace whatever fiberglass I could when I upgraded the vent and air conditioner on our Airstream Excella trailer.

We would be willing to provide a discount to the first person who uses it in their Airstream rebuild project. I am absolutely positive that you will love working with it and will be amazed by the performance.

All the best,
Hein
DIYvan
541 490 5098