1.1oz non dwr Bivy?

A bivy needs a DWR for most uses. I think DIYgearsupply has some for about $3.00/yd. Be tough to find any cheaper than that.

Ryan

You will absolutely want fully waterproof fabric on the bottom and breathable fabric up top. My bivy is eight years old now and the waterproofness has gone out of the bottom fabric which was a very unfortunate thing to learn during an extremely wet trip in September. A mixture of seam seal and mineral spirits will be getting made to do some painting this winter.

thanks for the advice, i figured he would continue to use his ground cloth. The bivvy would supply the sausage casing for him to stay a little toastier, We will go with dwr with bud mesh.

There are some fabrics that you can use wherein you can get away with not having a DWR, for example, any Tyvek or Polypropylene type material.

I have a fabric called Maxima ESD fabric, which is a tight weaved, non ripstop polyester, which is pretty water resistant without a DWR.

But any light weight nylon fabric you will want a DWR. If you're really into MYOG, i suggest getting some non DWR and fairly breathable 1.1 oz nylon, and then applying your own thinned and thin coating of silicone adhesive for a truly *durable* "D"WR. Most DWR's are not really that durable.

If you are interested in this idea let me know, and i will post more specific instructions. I've done with several kinds of fabrics so far, and if you do it right, it works great and will last longer than any other DWR out there except EPIC which it is trying to re-create/mimic. Basically, i think it's more durable just because it's a significantly thicker coating than the fluorocarbon, wax, silicone spray, etc based DWR's.

As regards bivie's, i've gradually come to the conclusion that for most conditions, i really only want a waterproof fabric on the bottom and a water resistant fabric to about the knees. Everything else can be mesh/bug net. Bug net/mesh will cut wind a little, but is breathable in call conditions. In some conditions, tightly woven single layer fabrics can ice up some and become rather non-breathable. This is assuming use of a tarp of some kind btw.

JMO, and probably not one shared by the majority here.

I am building a bivy with silnylon 2nds for the bottom and M90 on top.. wasn't too expensive.