Ripstop Inners — When to Use

An inner tent will make the tent warmer, it will block spindrift, it will block really cold drafts, it will deflect condensation coming down from the roof. It will not prevent frost from forming on the inside though: when it’s cold enough, you get it.

My summer tunnel is single-skin; my winter tunnel is double-skin.

Cheers

Like Roger mentions a rip stop inner is great for winter.

Thanks Roger — was hoping you might post.

“It will not prevent frost from forming on the inside though: when it’s cold enough, you get it.”

I assume you mean the inside of the inner wall? or the outer wall? 

Thank you Stephen.

I am just trying to decide if I want a full WP/B bivy for its versatility but less space, or for the inner and get a little more space to pop my gear out of the spin drift as well.

Hi Will

Yep, on the inside of the inner tent.

When it is -15C outside, it might be -10C at the very best inside the inner tent – more likely -12C or -13C. When you breathe out, moisture goes into the air, condenses on the inside of the inner tent, and becomes frost. It has no choice.

You have not lived until you have sat up in your tent one rather cold morning, brushed against the frost on the inner tent, and had it fall down the back of your neck. A unique experience. :-)

Of course, if I then get up (carefully) and light the stove for a warm drink for breakfast, that frost might melt, and drip. Sigh. A quick wipe with a soft sponge at just the right time is indicated.

Spindrift – yeah, can happen if the windward end is not closed. See When Things Go Wrong for more details.

Cheers

Roger — thank you. I have had the breath/frost dilemma many times on just my tarp, and once in a blizzard in West Virginia actually had breath icicles on the tarp of my Notch… breathcicles?

Excellent info. Thank you!!

I suppose  do have one more question — in terms of mitigating condensation in down sleep systems — would a ripstop inner be better than an event bivy?

I understand this has to do largely with where in system the dew point occurs, but just generally speaking to more experience winter campers.

Opinion!
With an inner tent, at least the wet surface is some distance from your down. With a bivy, it is probably touching you down.  YMMV.

Cheers

I last used an eVent bivy under a tarp on a low single digits F night, with a 0F bag. I was horrified to find the inside of the bivy – and the shell of my bag, encrusted with frost in the morning. Perhaps some operator error, but I switched back to using a Hilleberg with a ripstop inner after that and have never encountered a similar problem. As Roger said, keeping the ‘inner’ fabric away from the bag is the best way to avoid moisture transference.

This is a good discussion of the challenges of bivies: https://40yearsofwalking.wordpress.com/2011/07/04/the-bivy-condensation-conundrum/

for non winter applications it will help block wind blown rain …. and reduce drafts from the wind … this may be more relevant for tents whose outer cant be slammed right to the ground

theres several threads about this on BPL over the years

also the temp difference may be significant … years ago BPL measured a 17F difference between the outside temps and a sealed up solid inner on the terra nova laser comp ….

as an owner of a laser comp i cant tell you the exact difference … but it is substantially warmer with the fabric inner than a mesh inner (which i have several tents with)

as to bivies … IMO they are a last resort for when you need to be in a snow cave or an exposed ledge … the condensation issues arent worth it unless yr using synthetic (or a synth overbag)

i also have an ID event microbivi and have woken up to frost on the inside … it wasnt too bad and a quick shake handled it fine … but a solid inner is superior to deal with such

;)

years ago BPL measured a 17F difference between the outside temps and a sealed up solid inner on the terra nova laser comp ….

Although anyone inside the tent might die of CO poisoning after a while.
Chancy stuff.

Cheers

roger …

last u heard Will R was alive and well =P

Also, the ground level fly in combination with the nylon inner tent are very effective in retaining heat – on a cold March morning I measured the outside temperature at 33 F and the inside temperature at 50 F, a seventeen-degree difference.

https://backpackinglight.com/terra_nova_laser_photon_tent_review/

OK, I see. But the tent was not sealed up. Instead it just had zero high ventilation, so it acted as a hot air trap – and a condensation bath.

Cheers

zipped up and slammed to the ground … i call that sealing (ork ork) =P

its also the air gap between the solid inner and the outer acting as an insulator

on clear non-windy nights a solid inner double wall tent can be MORE condensation prone than a mesh inner IME if one is not careful …

a few nights ago we camped out before a climb in a solid inner tent with it mostly sealed up as my climbing partner hates the cold … when we woke up there was substantial condensation on the fabric inner …. if we had opened up the tent more (inner and outer) that would have been reduced …

still the best article on the subject …

https://backpackinglight.com/single_wall_shelters_condensation_factors_tips/

perhaps BPL should come out with one for double wall (mesh and solid inners) as these are now going UL as well ….

;)

I remember waking up one sunny morning in the snow fields to find that the inside of the tent was bone dry. I had left the ventilation ports at both ends of the tent open, and a gentle breeze had blown through all night. It was lovely!

OK, hardly ‘warm’, but we soon fixed that.

Cheers

I always use a solid (breathable) inner tent plus fly when backpacking in the Pacific Northwest Cascade mountains.  Night time temps are usually in the 30-50 F range because I try to avoid warm weather for backpacking.

The solid inner tent is warmer and less breezy than a net inner tent.  While sleeping I can count on a 10 degree difference between the outside and inside air temperature.  While moving around inside the tent the temporary inside/outside difference can be as great as 25 degrees in the upper portion of the tent.

It is the temporary 10-25 degree temperature difference that is the real plus for me.  The difference between, say, a breezy, wet 40F outside environment and a calm, dry 60+F inside environment is huge.  It allows me to change out of wet clothes in comfort.   I’m on my knees when changing clothes so my temperature sensitive upper torso is in the warmest part of the tent while doing so.

I’ve found tents with pyramid or cheese-wedge shaped tops are best at giving me the temporary upper- tent heat increase.  Their small volume and shape seem to trap or concentrate the warmth from my body better than dome or tunnel shaped tents.

Other things being equal, smaller tents get warmer faster than larger tents.  Number of people in the tent is also a factor.  Two people moving around inside a small tent will heat it up much faster than 1 person in a large tent.  I recall a winter trip with temps around freezing where 4 of us slept in my 3 person tent with solid inner.  While changing out of our wet clothes inside it was warm enough to sit around naked for awhile.  Must have been around 70F.