Exped Synmat UL durability

I've got one also, used in heather, spiky camp sites. no problems so far.

Used inside tent, if using with a Tarp, or want extra protection use a ground sheet.

You don't have to buy one from Tent maker, try going to a local builders suppliers, ask if they have Tyveck, looks like thick paper, but very tough, get them to cut to size you want.

Shouldn't cost to much, light and can be folded up small. Unless camping on non rocky grass, sand, I use it myself, also stops tent groundsheet getting holed.

My UL7 has been able to cope with my heavyweight personality/torso pretty well so far with no probs.

I think manufacturing standards are really important as well as materials and design, though - seem to remember a whole bunch of unhappy Thermorest Neoair owners in the first 12 months they came out who experienced unrepairable leaks around the valve, and others experinceing seam bonding coming apart. Don't hear of that happening now, so imagine they got their manufacturing act together. In contrast, I've heard very few problems concerning the UL7 so far. It doesn't look super-tough, however.

As an alternative to think about to Tyvek for a groundsheet/sleeping mat protector, you might want to check out Evazote, which is a hi-tech dense foam you can buy in thin sheets quite cheaply. Big advantage this time of year is that it's a really good insualtor, as well as being pretty tough and I think from memory, waterproof to boot. . V highly rated on the Backpacking Light site in the USA where it's a bit better known.

One advantage of buying a sheet of material of course is that you can save weight by cutting out a custom shape eg to just fit under your mat.

 I've used Tyvek quite a lot now, I've yet to have any water come through it. It's normally used as last bit of insulation/protection, before outside finish, brick/wood/etc. goes on.

 I would need to compare with same bag, tent, mat, etc. to say if it makes a differance to insulation. I suppose being another layer between you and ground, may make at least a bit of differance.

huskyman wrote (see)

 I've used Tyvek quite a lot now, I've yet to have any water come through it. It's normally used as last bit of insulation/protection, before outside finish, brick/wood/etc. goes on.

 I would need to compare with same bag, tent, mat, etc. to say if it makes a differance to insulation. I suppose being another layer between you and ground, may make at least a bit of differance.

 Re. Tyvek.

 I've seen that Tarptent supply it as an option, groundsheet for their products.

 Must not be that bad then, or I don't think Henry would recommend it.