Zipper Weight?

a #3 26" one way separating zipper weighs 9 grams

I would use #3 on floor and WR #3 or #5 on fly

-Tim

Thanks a bunch Tim. I was sort of leaning in that direction as well. The water resistant #5 looks like it will make sewing easier as I won't need to do a storm flap.

I'm still undecided about attaching the floor. I'm going to do perimeter netting attached to the fly. Just using an internal ground sheet seems like the easy way to go but my wife wants a continuous barrier against creepie crawlies. So I either sew the netting to the roof and sew the floor to the netting, or use a zip for one or the other. We're talking 40' of zipper, or somewhere around 6-8 ounces.

If you use the WR zipper it would be a good idea to make sure it is well above the ground. It is, after all, water "resistant". Standing water will probably leak through. They don't specify a head for this item.

40 feet of zipper? I think a design change could fix that. I'm not sure exactly your plan but you can attach the fly/net/floor in all areas but the door where you use the zip. This should use much less zip. Since the zip is the heaviest of the materials used you want to keep it limited as much as possible. I only use as much zip as i need as it quickly adds to the weight (even at 9grams for 26")

-Tim

Jim,
Zip out floors would be great because they would make floor replacement easier after the inevitable abrasion, and allow use of the floor separately.
Trouble is that after alloy poles, zippers are probably the heaviest item in a tent. The "water resistant" zippers can be high quality, and are used by many companies on rainwear without leakage; however, they are quite heavier than the uncoated kind. In order to make the lightest durable tent, my solution to this issue has been to design floors to sew on after everything else with one continuous stitch line all the way around the tent border. Even with a faux lap fell seam, this requires only removal and replacement of two seams to replace the floor.
Zipper weight varies greatly, but my guess is that the 40 foot coated zipper, with stitching and pulls, will add at least a half pound to your shelter. I believe that is the reason many carry an ultra light weight under floor protecter that can also be used separately, as for example, when something is needed to go underneath a sleeping bag in a shelter. Some of the small tarp tent companies sell extremely light floor protecters.
Hope this is helpful.

Thanks all.

After further consideration I won't be doing a zip-out floor. I'm going to start out with soffit vents/sod cloth and a loose floor. If the wife rebels then I'll sew it in.

The water resistant zipper for my peak vent should work well. It will have a storm channel behind it but less leakage is better than more.

I'll post my pyramid design issues in a new post.