Plywood vs. Thermax hexayurt

[Irreverent Moniker]

I'm thinking about doing the whole hexayurt thing this year, since I'll be there sunday through monday I could use a more "luxurious" living space.

I was thinking about either making a pre-fab plywood building, where I just have to pop some bolts in to get it constructed, or one out of reflective insulation sheathing, and either tape it on site or make a fold-a-yurt.

The plywood building would be MUCH cheaper. $5-7 a panel vs $20-25 a panel, and inexpensive hardware vs. $130 in tape. However it would also be much heavier. I also don't know about the insulating/heat-reflecting ability of plywood. If I painted it with heat reflecting paint would it be as cool on the inside as a traditional hexayurt made with reflective sheathing?

Anyone have any experience with either?

[jkisha]

I'm a hexayurt purist. Vinay has, IMHO, come up with a design that I have yet to see improved upon. Though many have tried, without success. (again IMHO) But beauty is in the eye of the beholder, I guess.

[Irreverent Moniker]

Oh yeah, no doubt. I'm using his design, just trying to decide about material. He talks about the plywood version too:

http://hexayurt.com/#ewbplywood

Though, if anyone did slightly improve the design, it's this guy:

http://www.youtube.com/watch?v=itb3VG6zcdc

[ConnieH]

I think plywood would be hot, as well as heavy, even with a reflective coating it still doesn't have much, if any, R factor. But, add FIGJAM's swamp cooler and you'd be good to go. IMO, putting together a plywood hexayurt would be a bitch, those roof panels can be tricky, even with the r-max. And then there would be my fear of the whole thing collapsing on me in my sleep, but I'm a worrier like that

[Ugly Dougly]

Yeah, the Thermax would add heat and sound insulation and be lighter too.

[lucky420]

I vote thermax. As far as sound insulation I don't think it helped that much. Trying to rest/sleep I felt like I was in a big dryer and sound was amplified. Then again we were camped at 9:30 and I and the state of my mind at times was probably a contributing factor...

[JStep]

This has been discussed on another thread, plywood is not a good material, it's too heavy and the structure would be too dangerous without a lot of extra reinforcement.

[Irreverent Moniker]

Thanks for the input guys. My main reason for thinking about going with ply was cost...but I just ran up to home depot and they have reflective sheathing for $10 a sheet. Much better than the $25 I'd seen before. I'm also going to go with the smaller one (41 sq ft) to save on tape. I think I can actually get all the materials for under $100.

[jkisha]

Damn, I've never seen 1" insulation panels going for that cheap at Home Depot here in L.A. At that price I'd be tempted to add a third room to our yurt.(My partner would kill me!)

[burner von braun]

Be sure the insulation boards are 1" rigid foam, and not the beaded styrofoam type which are no good at all. ( get Thermax, Tuff R, or Super Tuff R) The insulation properties of foam boards vs. plywood is important. I agree with JK, that Vinay's original design is brilliant as is, I sketched and modeled derivatives (fun to do) but the original is pure and simple and strong. I went with the small 4x4' side panel version, fine for one person and your coolers etc.

Very happy with the results. The tape is expensive, but I wonder if you are getting too much? ($130) Certainly, as you noted, you wouldn't need that much for the small yurt. Don't forget to pretape the edges.

Have fun with it!


.

[Irreverent Moniker]

I think the stuff I found at Home Depot was R-Max, had reflective on one side. What does rigid foam feel like vs beaded styrofoam? It didn't say what kind it was, so I'm just going by feel/weight

[ConnieH]

I think the stuff I found at Home Depot was R-Max, had reflective on one side. What does rigid foam feel like vs beaded styrofoam? It didn't say what kind it was, so I'm just going by feel/weight

My panels are R-Max, but it has reflective coating on both sides. The foam you want is "polyiso" (short for something...) NOT "polystyrene" - it should say on the sheets somewhere what the material is...polyiso feels denser, heavier and doesn't break off in little pieces like styrofoam. The 1" panels of R-Max or Thermax also do not flex much at all, and really shouldn't because they will break. If the panels you found flex, they are the wrong kind

[Irreverent Moniker]

Hmm, I'll have to swing by again to double check.

[burner von braun]

The word you're looking for is polyisocyanurate. If by chance it isn't labeled on the board itself (I don't recall) the service desk at the store may run across the word when they look up the item on their computer. As CH said, there is very little flex at all, certainly no droop. Beaded styrofoam is like it sounds, little round beads of foam compressed together, majorly wrong for several reasons. Beware of polystyrene boards, which snap apart, The good stuff, so dense you could almost carve in it.

Sorry to rain on your parade, but it's probably gonna cost about $22+ per sheet unless they are trying to get rid of a batch on sale. 5 sheets for the small yurt. The other hexayurt thread has lots of good advice from seasoned pros, which helped me a lot last year, including a last minute question I had (thanks again!).

Good luck IrMo!

[jkisha]

I think the stuff I found at Home Depot was R-Max, had reflective on one side. What does rigid foam feel like vs beaded styrofoam? It didn't say what kind it was, so I'm just going by feel/weight

RMax is the right stuff, but it has reflective coating on both sides. Might you be thinking it's only reflective on one side because the second side has the printing on it?

[pockets]

I've been thinking for a while about the whole tape thing and I think I might have an idea; any feedback?

Rather than using tape for most of the joints, use contact cement (http://www.dap.com/product_details.aspx?product_id=37) to act as an adhesive for 1-foot wide strips of rubber/vinyl-impregnated fabric drop cloths. If the strips are a foot wide, it seems there should be plenty of strength from the contact cement (I figure it would be at *least* comparable to decent tape).

I wonder if we could even use ZipWall for the temporary joints and if nothing else could be used to help make a door panel. (http://www.homedepot.com/h_d1/N-5yc1v/R ... ogId=10053)

Any thoughts or feedback? :)

[ConnieH]

I've been thinking for a while about the whole tape thing and I think I might have an idea; any feedback?

Rather than using tape for most of the joints, use contact cement (http://www.dap.com/product_details.aspx?product_id=37) to act as an adhesive for 1-foot wide strips of rubber/vinyl-impregnated fabric drop cloths. If the strips are a foot wide, it seems there should be plenty of strength from the contact cement (I figure it would be at *least* comparable to decent tape).

I wonder if we could even use ZipWall for the temporary joints and if nothing else could be used to help make a door panel. (http://www.homedepot.com/h_d1/N-5yc1v/R ... ogId=10053)

Any thoughts or feedback?

It's been done, look up the hexayurt main thread - Mike (I think his name is Mike anyway) did some very interesting modifications that have worked for 2 years now, despite criticism from the hexayurt purists (JK )

A friend didn't have time to buy tape last year and used Gorilla tape with success, but it was a colder than normal year - not sure how that would hold up in 100 degree heat.

[jkisha]

Yup, I saw it, live on the playa.. And no, I would not recommend zippered construction. I guess what "works" is more a matter of personal opinion as opposed to engineering and functionality.

The one thing that makes any your a your is the compression ring. If that is compromised, there can be no stability. Fabric hinges are too loose to provide the compression. Having to support your yurt with two poles sort of defeats the purpose.

I really don't want to pick old scabs, but I can't in good conscious not comment on the reality of that construction method. At least then, if somebody wants to try it, they were apprised as to what to expect. Hey, you never know, it may just "work" for them too then.

[ConnieH]

Yup, I saw it, live on the playa.. And no, I would not recommend zippered construction. I guess what "works" is more a matter of personal opinion as opposed to engineering and functionality.

The one thing that makes any your a your is the compression ring. If that is compromised, there can be no stability. Fabric hinges are too loose to provide the compression. Having to support your yurt with two poles sort of defeats the purpose.

I really don't want to pick old scabs, but I can't in good conscious not comment on the reality of that construction method. At least then, if somebody wants to try it, they were apprised as to what to expect. Hey, you never know, it may just "work" for them too then.

I think the bottom line is that a lot of questionable construction methods (hexayurt or otherwise) have the potential to work on the playa, but some of the success could be just pure luck. A campmate had a shoddily constructed and unanchored monkey hut last all week last year, I swore the thing was going to blow away, but it never did.

Sorry to bring up a scabby subject JK, but he asked...I too am still a purist because I believe in the design because it's worked well for me and I don't like messing with perfection. Besides, the time and effort involved in making fabric joints doesn't justify the savings in cost to me, especially if it didn't work and you were back at square one.

[jkisha]

Yup, I saw it, live on the playa.. And no, I would not recommend zippered construction. I guess what "works" is more a matter of personal opinion as opposed to engineering and functionality.

The one thing that makes any your a your is the compression ring. If that is compromised, there can be no stability. Fabric hinges are too loose to provide the compression. Having to support your yurt with two poles sort of defeats the purpose.

I really don't want to pick old scabs, but I can't in good conscious not comment on the reality of that construction method. At least then, if somebody wants to try it, they were apprised as to what to expect. Hey, you never know, it may just "work" for them too then.

I think the bottom line is that a lot of questionable construction methods (hexayurt or otherwise) have the potential to work on the playa, but some of the success could be just pure luck. A campmate had a shoddily constructed and unanchored monkey hut last all week last year, I swore the thing was going to blow away, but it never did.

Sorry to bring up a scabby subject JK, but he asked...I too am still a purist because I believe in the design because it's worked well for me and I don't like messing with perfection. Besides, the time and effort involved in making fabric joints doesn't justify the savings in cost to me, especially if it didn't work and you were back at square one.

Not really a sore subject for me, I was more thinking about the guy that built it, he was pretty offended by my comments. But it's understandable, he put hours of work into the construction. I actually liked the idea he had for cutting the door into the roof, as I hated bending down to get in and out. But it cuts right into the tension ring and the yurt becomes less stable. So, we ended up building a second one with six foot walls for the main section and attached the four foot wall yurt to it for our bedroom. That way I only have to bend over twice a day!

Even with the six foot walls we argued about whether the walls should be horizontal or vertical. Turns out it doesn't make much difference.