What did I do wrong?

[SilvrSurfr]

I've quit trying to understand condensation under the tarp. I went on a somewhat rainy trip this weekend and hung my HG Winter Palace tarp high with the doors open. Low temps were 46 degrees at night. In the morning the inside of my tarp was coated with condensation. I went and checked on my buddy and his polyester tarp, a Grand Trunk Funky Forest. He had zero condensation on the inside.

It all seems kind of random to me. Sometimes I get condensation and sometimes I don't. Even if I thoroughly understood how condensation works, I doubt I could do much to mitigate it.

[Tehghost132]

From experience with setting up a tarp in my backyard, I get condensation on the inside of the tarp almost all the time. Not a whole lot you can do about it from what I've found. Pitching it wide and having a light breeze come through to help with airflow works a bit, but obviously you dont want this if its getting cold out. Try for a tarp with side tie-outs and use them, then try not to let your back slide against the tarp when you get in or out at night is the best I can tell you.

[BillyBob58]

except for my son (who had similar issues with his ENO Superfly) all others were in tents and not affected by the moisture issue as much.

Also, I didn't use a ground cloth, because I find in rain, water just pools and creates more issues.

Were they double wall tents? These tend to manage condensation much better than either single wall tents or tarps. The inner walls are breathable and a bit warmer( closer to your body heat and with an air layer between you and the coldest outside air hitting the outer wall). Of course, condensation can happen here also, but def less likely than any single wall shelter. I also get a lot more condensation in the back yard ( completely open and exposed and usually with wet grass and ground) than I do in a well sheltered spot in the woods. So far I have had no bad condensation problems when hanging in dense woods with fairly dry forest floor under me) A ground cloth might also help some in my grassy back yard(or anywhere), as I think ground moisture might add to the total vapor load which is waiting to condense against the ice cold tarp. That is another advantage your tenters might have enjoyed: ground was covered with waterproof fabric. Plus maybe more than one warm body in the tent, so temps a bit higher keeping the inner walls even warmer.

It's just the extra challenge of a single wall shelter. And with a large tarp, the inner temps will be even colder than in a smaller tent with maybe 2+ occupants. Try to allow for better ventilation and keep the tarp far enough away so it won't contact you or your gear.

That is an excellent article on condensation, AaronMB, as are most from BPL.

Also, consider sleeping with some sort of Shug style frost bib. If you can get most of your breath to condense on that piece of fleece hanging from a ridgeline, it will remove a large part of the vapor load which is desiring to condense on your tarp. Sleeping at 6*F in a sort single wall shelter( no tarp, but a HH overcover, which is breathable plus about a 6" diameter vent near my face), I was worried about a ton of condensation because very little air would be moving through like when I use a tarp with wide pitch. But I had no condensation at all, except of that piece of fleece. Without a bib, even with good ventilation and the tarp a good distance from me- or even no tarp- I have had condensation soak my quilt near my face.

[Bigmuddy]

I guess I don't quite understand the closed in tarp situation. Are you guys sleeping with a tarp tight enough that it acts like a single wall tent? Is this to prevent ambient moisture/ rain spray? Or to retain heat?

[Donk_67]

Bigmuddy, I attempt to pitch the tarp low to the ground when I'm expecting windy, or cold conditions in part to spill the wind some (loss of heat through convection) and partly to retain a smidgeon of body heat (tent like). I'm not sure the heat retention works all that effectly, but it seems like the thing to do. given last weekend's scenario, I'm thinking about reverting back to keeping the tarp high enough that I can easily peek out from beneath it while I'm in my hammock. Though I'm not sure how much less the condesation issue would have been. I take Shug's words to heart: condesation happens.