Is there a source for Silnylon like SMD uses for their ultralight floor option.

If it was 0.7oz/sqyd before coating you might take a look at the Impetus 1.2 at DIYGearSupply.com. It’s a silicone coated/PU Coated 15D rather than the typical 30D SilNylon and has a finished weight of 1.2oz/sqyd. At $10.35/yd I would probably move to a more durable cuben fiber floor material (either 0.74oz/sqyd or 1.0oz/sqyd) which would be lighter but about x2 the cost.

I agree Eric. If the coated is all that is available I think I would go with Cuben. In the mean time I think I will give polycro a try.

Thanks

I wonder what is the hydrostatic head of that impetus

regular silnylon – fabric 1.1 oz, coating 0.2 or 0.3 oz.

impetus – fabric 0.7 oz, coating 0.5 oz – since the coating is heavier, maybe it's more waterproof, also the combination of PU and silicone – that could be good for floor where you don't need that much strength but you do need water-proofness.

Jerry,
There was a recent thread in which Josh Leavitt adivised the HH was 1200mm, but later revised that to 900mm:

http://www.backpackinglight.com/cgi-bin/backpackinglight/forums/thread_display.html?forum_thread_id=68296

Doesn't sound like a floor material, but I ordered a yard to take a look at it as a canopy material. It may be too dark, though, for that.

For a floor, I can't see how you can beat the silnylon T-H sells, with over 3000mm HH and Dupont 6,6 nylon. Very strong, very waterproof, and very elastic to resist punctures. What's not to like? Well, there were comments that it is too "slippery." I think that concern arises when the floor is not staked taut. But if it is sraked taut, silicone smears on the bottom of the sleeping pad eliminate any problems for me. I can't sleep unless the tent is on level ground, so sliding is not an issue either.

I made bivy floor with TH Shield silnylon and echo your comments – it works pretty good

No Way! Patek Philippe? thats so UL!