Monday, 13 September 2010

Canvas yurt covers: The disappointing truth

Let's go back for a moment to 2006/7.

Her Outdoors put a lot of work into finding the right kind of canvas for our yurts. She talked to lots of people (they weren't always very forthcoming about their suppliers - not surprising as yurts were really taking off at the time and canvas was in increasingly short supply). She looked at lots of websites. And she settled on the unbleached 12-ounce 'waterproof, rot-proof, flame-proof canvas' everyone was using.

Sounds very reasonable. I can't see why anyone would do anything different.

We ordered hundreds of metres (yards) of the stuff, from two different suppliers. Her Outdoors made a cover for our first 18-foot yurt, we put it in the trailer and off we went.

If you've read this blog from the beginning (or the end, depending on which way you look at it), you may remember that August 2007 was very wet when we arrived in France. Very wet - outside and inside the yurt. So wet, we sought shelter in a house and Her Outdoors began to doubt her skills. Which are considerable (and award-winning).

Time passed.

We built the 12-foot Play Yurt and Her Outdoors made a cover. We moved into it. It rained. The cover leaked. And started to rot. (Waterproof, rot-proof, flame-proof, remember?)

We put the original 18-foot up for extra storage. It leaked a bit less. And was a bit less mouldy.

We put a new 18-foot up on a lovely dry beaten earth platform, with canvas from the second manufacturer. Just before a rainstorm. Which went straight through the cover, almost like it wasn't there.

Her Outdoors made a few calls. Here's one:

Professional yurt cover maker 1: 'Ah yes - 2007 was the worst year to buy canvas - the rot-proofing was water soluble. They've made some improvements.'

Here's another:

Professional yurt cover maker 2: 'Oh yes - you need to re-proof your canvas before you use it. Twice if you can. Otherwise it leaks. We'll send you some proofing, but you won't need any seam-sealer.'

More research revealed people who live in yurts full-time do not use canvas. (Which, among other things, needs replacing EVERY COUPLE OF YEARS.) Everyone's using some kind of manmade material, like polycotton, which costs many, many times more but will last for up to 10 years. (If you really need to know, use the comments thing below and I'll get Her Outdoors to give you all the details.)

Now, call me old-fashioned if you must, but if you sell something as 'waterproof' and 'rot-proof', it should be those things. The 12-foot cover rotted so badly, Her Outdoors had to make a new one before we could open this year. It lasted a few months (which would have cost 1250 GBP if made professionally - no wonder other yurt camps cost so much).

Last week, it rained for the first time since July. Again, inside as well as outside our yurt (we re-proofed the guest yurt and Play Yurt at the start of the season and they held up pretty well. We couldn't re-proof our yurt 'cos the material was so new, the proofing ran off - yes, it's actually proof-proof).

We found how the water was coming in - and will be ordering some seam sealer in the next few days.

14 comments:

becky said...

Hi Folks,
Sounds like a frustrating experience. Did you get the Sunforger Marine treated canvas? That's what I've seen recommended the most.

Many tipi makers and some yurt makers (who aren't using the architectural fabrics) coat their canvas with a high quality latex paint like the environmentally friendly "SureCoat", diluted with water before applyiing.

If you have more questions, you might contact tipi maker Debra Williams at www.sagebrushtipiworks.com.

Best of luck with those covers,

becky kemery
Author of "YURTS: Living in the Round"
www.yurtinfo.org
Yurtlady on Facebook

P.S. Thanks for carrying my book on your bookshelf!

the devolutionary said...

Hi Becky - thanks for the info and thanks for coming back to the blog.

Her Outdoors tells me the Sunforger Marine is one of those very expensive fabrics - something like 30 bucks a square metre instead of the few bucks we paid. If we only had one yurt to cover, that might be fine, but we came here with eight!

We'll definitely check out that paint, though. In fact, it's the next thing I'm going to do... See you again soon, I hope.

Anonymous said...

oops seems my comment might have gone awol.
It was subrella fabrics that were prohibitively expensive. The prices for sunforger are great. How long does it last, can anyone tell me?
of course I can't find a supplier in france yet!!!

Anonymous said...

I'm sure you have seen some of our machines In midwestern America and in some airports in Europe.

You put your suitcase in, it rotates very fast around the case, wrapping it up securely in multiple levels of heavy duty non-biodegradable weapons-grade military cling film, protecting it from water, rot, and total thermonuclear annihilation.

Am shipping you over one of our machines for you to wrap your children, guests. furniture, etc

Hope this helps in some small way alleviate the problems you've been having with our canvases

yours sincerely

Maj. Norman Singen Polevaulter (Rtd.)

Fred Yurts said...

I wouyld say that canvas is never 100% waterproof. If your canvas is very dry and there is a sudden torrential downpour, then the fibres won't swell quick enough to remain totally waterproof. Obviously if it is pouring in, then you have a problem with your sewing - either you are using the wrong sized needle, or the wrong type of thread (some thread will swell, some won't. Also your top and bottom tensions need to be right, as well as your stitch size. All of these will affect how waterproof your cover will be. I would also say don't use polycotton 12oz just because everyone else is using it - pure cotton wears better and has a softer more natural feel over time, whereas canvas with polyester in will hold dirt more I have found, and with age, won;t look as lovely, although it shrinks and stretches less and is harder to tear. I like a heavier canvas myself... Also final point - do not ever have canvas folded up even slightly damp - it needs to breathe, and should be aired regularly and be bone dry before storing. Am looking for help about shrinkage and guess what - no info on the net - its a mystery!

the devolutionary said...

Hi Fred. Your comment made me re-read this post (it's been a while).

If read literally, the post exaggerates the water issue. The rain didn't come through the canvas like it wasn't there. It just came through far too much and we didn't want it at all. We've since learnt canvas will leak the first time it rains, then tighten up and should be fine. We now rub exterior silicon sealer down the seams of our own yurts to keep the water out, but will be switching to polycotton when these covers need replacing.

For our two guest yurts we switched to polycotton last year and the covers survived the winter in excellent condition. Not a hint of black spotting.

On the shrinkage issue, canvas is appalling. I don't have the figures and Her Outdoors isn't here to ask, but from memory it's in the region of three per cent. Do not make a cover based on that. Ask some suppliers (like the one Becky mentioned in the comments above) and talk to someone who's honest.

emma said...

Was doing some yurt pricing research and found your blog. I have learnt much about shrinkage over the years and most producers end up with a difference. I use polycotton as it only shrinks 1%-2%. Cotton shrinks about 3%. Though I have even bought polycotton with a 3%-5% shrink. The key is to ask the seller when you are buying as each manufacturing is different. Also another key element to stopping the leaks is the construction of your seam. I often use silicon when I make put in PVC windows as the sewing holes will not seal up in the PVC. Welcome to ask any advice emma@threadform.com

the devolutionary said...

Hi Emma and welcome! We do the same on our windows, which seems (!) to work pretty well. But we're moving away from windows in the ceiling in the future. The polycotton we use isn't supposed to shrink, but there may have been some. One of our yurts is behaving a bit strangely...

Anonymous said...

http://www.wisegeek.org/how-can-i-waterproof-canvas.htm

According to the above source, silicon is a no go, as it destroys the fiber of the canvas. Can be good to know!

Also remember, yurts are built to be lived in full-time, as the nomads who invented them do. Heating takes care of a lot of problems automatically. Leaving a yurt just sitting somewhere without heating it will probably be it's end in a near future. You probably did know this though.

All the best.
/Pontus

Sonny, the Chinese Irishman. said...

http://www.wisegeek.org/how-can-i-waterproof-canvas.htm

According to the above source, silicon is a no go, as it destroys the fiber of the canvas. Can be good to know!

Also remember, yurts are built to be lived in full-time, as the nomads who invented them do. Heating takes care of a lot of problems automatically. Leaving a yurt just sitting somewhere without heating it will probably be it's end in a near future. You probably did know this though.

All the best.
/Pontus

Anonymous said...

I have lived in my 15 foot diameter yurt in New Mexico for 4 years, and it has leaked a little bit near the crown if I didn't set the covers on just right, but it has been fine otherwise. I built my yurt Mongolian style, useing the typical Mongolian cover materials. When I investigated the price of canvas, I just ordered one 20'x 20' heavy duty canvas tarp for the roof, and several of the same for the walls, cutting all to fit. Then I ordered canvas dropcloth material (the kind used by painters) in the same sizes, and made that into an outer cover. So, my yurt wears an undershirt, several wool sweaters, a raincoat, and an overcoat. Cheap and works great. NM is fairly arid a climate, just like Mongolia, so I would not recommend setting up a woolen yurt in a wet or humid climate.

Nikky Warden said...

Hi there. ,What do you use to seal your seams?
We are re proofing our canvas with nikwax

Dave said...

Hi, friends.

I notice the comment about using silicone. As I understand it it degrades in sunlight so it may not in itself be responsible for rotting canvas but where it is in the fibres it will (anyway) inhibit the cotton from drying out in any case.
My *feeling* is to avoid silicone and resin (two part type stuff) in general and find water-based alternatives. Solvent based paints and acrylic or even worse the old style "polyurethane" varnishes tend to trap moisture under them. The main reason marine varnishes are super expensive (so I have heard, I am no 'expert'), is that they have an additive that inhibits the degradation by UV. Like any "plastic" they degrade with prolonged exposure to the sun.
For the same reason that coverings for polytunnels are more expensive if they are rated to last for 5 years rather that 2. They just have more of the magic (read expensive) chemical added. Correct me if any of this is incorrect. (ah good sentence structure there...) I am interested to know more, as I am struggling with a badly decaying yurt cover as we speak, or talk, or rather as I type, well almost at the same time, what am I? An octopus....

Your humble servant

x dave

the devolutionary said...

Hi everyone - sorry about the delay in responding. I've been blogging at thedevolutionary.wordpress.com for a few years now and don't check here very often.

Nikki - Nikwax is the best we've found here, although I'm not sure if the Sunbrella fabric on the two most recent covers has any proofing. It's been a great material so far, with no leaking!

Dave - sorry to hear about your badly decaying cover. I know the feeling well. If you look on the wordpress blog, about a year ago, you'll see how badly our old canvas covers did. Specifically, this post: https://thedevolutionary.wordpress.com/2014/11/09/from-shabby-to-chic-in-a-day/

Anonymous, above, looks like they've found a good and cheap solution. Sunbrella's good - but it ain't cheap...