Cuben floors?

Big cuben debate going on another thread.

I think the overall jist is that cuben looses it's waterproofness after repeated folding twisting ,…

I don't know what to think though. I have had good luck with polycryo and it's a lot cheaper and can be had at Home Depot:-)

It depends on the thickness of the cuben and the abuse you put it through.
Some here have 1.25 ounce/yd cuben pants that seem to take kneeling in water just fine.
I'd be pretty carefull of the .34 o/y.
It is clear the use/stuffing greatly accelerates the degradation.

The real answer is many months away, as testing will most likely be a slow process, somewhere in the priority list, but most likely not at the top.

Cuben is not slick, just expensive. If you sleep on a waterproof pad (closed cell or
inflatable) you don't really need waterproof so I wouldn't worry about the ongoing debate.

The ongoing debate is a case of perfect being the enemy of good.

"Are they slick like spinn?"
No

"what thickness of cuben would be durable for a floor and could it be used w/o a ground sheet?"
IMO, 1.26oz (CT3.5K.18) is the best. It uses the more durable .18 mylar layers so it's much more abrasion resistant than anything lighter which use 0.08 mylar. 1.5oz cuben is also a good choice, just slightly heavier than needed because you don't really need that much spectra in a floor IMO.

I happily use my HMG Echo I without a groundsheet and it has a 1.5oz cuben floor. IMO, with reasonable site prep (ie. remove sharp stones & sticks) no groundsheet is needed. When UL hiking, I never use a groundsheet with any shelter and 1.5oz cuben doesn't seem any more susceptible to damage than any of my nylon flooded shelters. Admittedly, I only have about 5 nights of use on the Echo I.

"I think the overall jist is that cuben looses it's waterproofness after repeated folding twisting
I don't think this has been established or even is likely to be true. I believe all that has been shown in a very limited test or two, is that new 0.7oz cuben has a HH around 420mm when new. Presumably, the other light variants (0.33, 0.48, 0.51oz) would fare similarly as they use the same mylar layers with varying amounts of spectra strands. Heavier cuben (ie. 1.26oz, 1.51oz) uses significantly thicker mylar layers. No one has HH tested these yet but I'm guessing they are far more waterproof.

"It is clear the use/stuffing greatly accelerates the degradation."
Have I missed something? I haven't heard any evidence or suggestions that use degrades the waterproofness of cuben.

"Have I missed something? I haven't heard any evidence or suggestions that use degrades the waterproofness of cuben."

First off, I think there is a lot opinion and partial science going on in that discussion, but,…
People are claiming that the hydrostatic head has been reduced in their test cuben after repeated compression. Something about the mylar component not being as resilient or something or other.

And as stated, a ground cloth doesn't have to have a high hydrostatic head rating, unless you are one of those backpackers that seems to be attracted to pitching your shelter in a depression. And there are a lot of those:-)

"IMO, 1.26oz (CT3.5K.18) is the best. It uses the more durable .18 mylar layers so it's much more abrasion resistant than anything lighter …"

Agree. We should see some HH specs on the 1.26 oz weight soon. They may even include specs after simulated use – even better.

Still like the way silnylon repels dirt and water, though. Much easier to fold up the shelter clean and dry than it was with PU coated floors. So still looking for higher HH 30 denier silnylon for floors.