Yurt foam materials

[llamafilm]

Hello! I’m planning to build a hexayurt this year and I’m looking for advice on materials. My local Home Depot carries 2 types of foam insulation:
Rmax polyisocyanurate (ISO)
R-Tech expanded polystyrene (EPS)

It sounds like EPS is more environmentally friendly to manufacture and it can be recycled. But if I remember right, it crumbles a lot if you don’t protect the edges. Does anyone have experience with these 2 materials, or is there a different type I should look for?

I will use 4x4ft walls so for this size I’m thinning 1” thickness will be strong enough.

[Canoe]

If you want or expect the hexayurt designs to work on the Black Rock Playa, handling its temperatures and winds, then you need to use the "recommended" materials. Specifically, the structural foam sheets (and tape the edges with foil tape) of the recommended thickness and the hexayurt tape (bi-filament 220 lbs, six inches wide).

If the year is mild enough for no/low winds, you might get away with less. But you will not enjoy the results if there's normal playa winds.

Although your playa neighbours may be amused to watch your hexayurt explode in the wind, they'll be less amused if its remains blow into their camp. And they will not be amused at the bits of foam blowing around, and neither will those who can fine you for the mess or even kick you out of BRC.

[llamafilm]

@Canoe yes I will tape the edges and I've already bought the good 6" tape. My question was about the foam panels. Structural foam sheets are available in many different compositions and brands, so that's why I'm asking for help here. You're telling me to use the "recommended" kind, but recommended by whom?? That's what I came here to find out!

[burner von braun]

Polyisocyanurate is the substance you're looking for llamafilm. I think R-Max is often suggested, though here where I am, I was only able to locate and purchase a brand called Tuff-R (they also make double foil sided [both sides] Super Tuff-R as I recall), and I ended up having to have the local box store order it.

Definitely don't get anything that is comprised of the little styrofoam beads, or the kind that snaps easily, that's the stuff that explodes in even moderate wind, as Canoe pointed out. Polyisocyanurate, on the other hand, is very dense, and it is playa proven, recommended by all, starting with the inventor of the hexayurt, Vinay Gupta.

There are a ton of great hexayurt threads that do a deep dive here on eplaya. I encourage you to read through a few of them. They contain a lot of details and personal modification ideas, some better than others.

Good luck with your build!

[Canoe]

I'm not going to try and replicate dozens of posts & threads on hexayurts, with materials and how-tos, alternate materials and design variations, nor a quick answer that creates fractured information. The threads cover what type of panel and what thickness of panel for which size of hexayurt, along with why the 'power band' is necessary, and why the tiedowns matter, etc., etc., etc.. Too often someone gets fractured information that leads them to think "I only need this info", a quick answer, and then they move on to a build that fails. It's fractured information to you (and maybe you do have all of the other bases covered), but quick answers leaves fractured information sitting there as a time bomb for someone else coming after you.

(For example, you mention that "I will use 4x4ft walls so for this size I’m thinning (thinking?) 1” thickness will be strong enough.", but you don't specify which design you're following, or if you're not following a proven design and have come up with a 4x4' wall section solution. We've no idea what the wind-shedding nor wind-loads will be like. There's no way anyone can say one inch is fine without knowing the design. Guaranteed there's several someones who can say that 1" was fine for theirs, it should be fine for yours. Only without knowing the design context, and if theirs was in a walk-in-the-park year, that's not a reliable endorsement.)

There's other hexayurt resources on the internet, but some are copies and provide fractured information. How do you know which is which... I don't recall one "here's how to do it reliably" thread on eplaya, so I'm afraid that you're going to have to assemble the information yourself.

Eplaya search sucks.
Use google to search eplaya for the whole collection of hexayurt threads.

Some are short & sweet. Some are somewhat epic. Some are on a particular size of yurt. Some are a waste of time.
Unfortunately there isn't a filter to exclude "bad ideas", so you're going to need to read a number of threads before you are convinced you've got the consensus. More important than the consensus, is to watch out for what was actually implemented and feedback was provided on how that did or didn't work on the playa, with the heat and the wind. So often a design or material variation was fine - if it's a low wind walk-in-the-park year - misleading others into thinking that the design or material variation(s) was fine, only to have the one they build that way disassemble itself in the heat or wind, and they have to search downwind for the (broken) pieces of their yurt, and for all of their distributed belongings. So do ask your questions to the bottom of an appropriate hexayurt thread, so we can keep all of the information, and feedback on design or material variations, together (as much as possible with ___ hexayurt threads).

[llamafilm]

Thank you for the replies! I totally understand your point about fractured information, and keeping information organized in existing threads. I've been reading several sources, compiling my own opinions as you always have to do with online research. I'll continue doing this. I did find a write-up using 4x4 walls but I'm still planning.

BTW, I love the "bad idea" filter! Let's get someone to invent this