Author Topic: The truth about single skin / hybrid tents  (Read 2015 times)

Troggy

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Re: The truth about single skin / hybrid tents
« Reply #15 on: 16:54:02, 24/06/18 »
Well, I suppose it depoends on a) weather conditions, b) ventilation c) possibly, the design of the tent and if you do any cooking/heating in the tent. I've got a double rainbow, which is single skinned, although I have a breathable, clip in liner that is made or it. The mesh inner, therefore, should deal with the condensation as some folk have positted. but I've sewn in panels of solid inner tent material because...basicaly I'm a wimp and want a warmer tent. I've got to go out in it yet, having just bought a replacement crosspole sleeve off Tarptent.
Although the stitching, fitting looks a tad amateurish (a lot amateurish!) I feel a lot more comfortable with the thought of facing the elements in it.   

richardh1905

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Re: The truth about single skin / hybrid tents
« Reply #16 on: 18:17:08, 24/06/18 »

.... I've sewn in panels of solid inner tent material because...basicaly I'm a wimp and want a warmer tent. I've got to go out in it yet, having just bought a replacement crosspole sleeve off Tarptent.
Although the stitching, fitting looks a tad amateurish (a lot amateurish!) I feel a lot more comfortable with the thought of facing the elements in it.


Interesting idea.

scottk

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Re: The truth about single skin / hybrid tents
« Reply #17 on: 21:23:05, 24/06/18 »

You can be the most competent camper in the world, you will never be able to stop condensation in a single wall tent, especially ones made of DCM, like the Zpacks tents...It may be waterproof, but it isn't exactly breathable, so without leaving the door or doors open a bit, even in the rain, there is nowhere for moisture in your breath to go except onto the inner surface of the tent wall.
 The driest tents are two wall tents which have an inner tent that is mostly made of no see-um mesh. 
The mesh is highly breathable, allowing moisture to pass through and be carried away by the slight draught that the design sets up between the inner and outer walls, before it has time to condense on the inside of the rain fly.
 Most of the best new tent designs utilise mesh inner's as it is the most effective method to stop condensation.  Two wall tents are heavier though, so it comes down to whether you prefer to carry a lighter base weight or being able to enjoy a dry nights sleep.


That's a very basic explanation but doesn't really explain the vagaries of weather, temperature, volume, effect of people in tent, wind etc. There are too many variables to state that it is black and white. All my tents are double wall and none are free from condensation unless I have decent ventilation and even then it's not a given. You must choose a tent to suit yourself and the conditions in which it will be used most of the time.

NeilC

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Re: The truth about single skin / hybrid tents
« Reply #18 on: 08:12:35, 25/06/18 »

That's a very basic explanation but doesn't really explain the vagaries of weather, temperature, volume, effect of people in tent, wind etc. There are too many variables to state that it is black and white. All my tents are double wall and none are free from condensation unless I have decent ventilation and even then it's not a given. You must choose a tent to suit yourself and the conditions in which it will be used most of the time.


I think he's maybe referring to condensation on the inner tent? And I think he's wrong that you need mesh to ensure this. I've had various tents over years with non-mesh inners and all of them have handled condensation on the inner tent fine but all of them, including my fairly meshy TN Coshee have had condensation on the inside of the fly - it's unavoidable as far as I can see. Warm wet breath meets cold waterproof sheet = condensation.


The thing about the ventilation - it has another name - it's called "freezing cold draughts" depending on the weather!

NeilC

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Re: The truth about single skin / hybrid tents
« Reply #19 on: 08:26:14, 25/06/18 »
It's weird all these reports of condensation, I've a TN Jupiter Bivvy which sits (like all bivvys) against my sleeping bag and never transfers any condensation at all - Its as if single skinned shelters really need to have a minimal volume and PROPER breathable fabric so the action of you body heating and breathing the small amount of volume within the shelter slowly expels air OUT through the tents skin


Roy


I think you're right about the volume.



They don't seem to have had much luck using breathable membrane fabrics (like Goretex) in tents. It sort of works OK in dry cold climates but very badly in high humidity like we get in the UK. I think the big air gap in a tent isn't ideal for breathable fabrics. Moist warm air will still condense on it, there's no getting away from that. Previous forum posts have established that Goretex doesn't work like the infograms show (vapour just passing through it unchecked). Water adsorbs into he inner layer and diffuses across it to the outside ,but the opposite is far harder so you get a directional fabric. For that diffusion to work well, it really helps if the humidity and temp on the inside face of the fabric is much greater than the outside face. In near 100% humid Welsh rain conditions and a couple of feet air gap, the difference is very slight and so the water movement is very slow.

April

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Re: The truth about single skin / hybrid tents
« Reply #20 on: 08:51:50, 25/06/18 »
Warm wet breath meets cold waterproof sheet = condensation.
The thing about the ventilation - it has another name - it's called "freezing cold draughts" depending on the weather!

 ;D Spot on. On Saturday we pitched close to 800m on a Lake District fell. The wind chill was about 3 or 4 degrees, if we'd had an all mesh inner we would have been freezing inside the tent. MT says he camps in the Surrey hills, the highest being 292m, his tent might suit for the camping he does but wouldn't suit anyone wanting to camp up north higher up.

Condensation can happen or not happen depending on the conditions. Having an all mesh inner does not stop condensation.
"Who would've thought...... you are light and darkness coming through" words by Tim Armstrong

Owen

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Re: The truth about single skin / hybrid tents
« Reply #21 on: 13:03:25, 25/06/18 »
In any tent you are the main source of water vapour, from your breath and sweat. Water vapour molecules are very small so they will pass straight through the weave of un-proofed nylon. When they hit the cold proofed outer flysheet they can't go through it and as it's cold condensation forms. If enough condensation collects it will form drips, if your tent's inner is made of tight weave solid nylon these drips will spread out due the the surface tension and dry quite quickly. On the other hand if your tent has a mesh inner the drips will go through and land on your sleeping bag. So, having solid nylon at least above you is a good idea. Having mesh on the sides of your inner tent will offer less resistance to wind, whether this is a bad or good thing will depend on the ambient temperature. Having well designed vents in the outer flysheet will go a long way to reducing the build up of condensation on the underside of the fly.
       

richardh1905

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Re: The truth about single skin / hybrid tents
« Reply #22 on: 14:17:22, 25/06/18 »

;D Spot on. On Saturday we pitched close to 800m on a Lake District fell. The wind chill was about 3 or 4 degrees, if we'd had an all mesh inner we would have been freezing inside the tent. MT says he camps in the Surrey hills, the highest being 292m, his tent might suit for the camping he does but wouldn't suit anyone wanting to camp up north higher up.

Condensation can happen or not happen depending on the conditions. Having an all mesh inner does not stop condensation.


This is what puts me off buying an ultra lightweight tent with a mesh inner (as well as the cost). What is the point in pinching a few tens of grams on the inner if you are freezing and have to take extra clothes or a warmer bag?


They are maybe a good idea in more benign climates, but for Lake District fell tops, I would say not.
« Last Edit: 07:53:30, 26/06/18 by richardh1905 »

alan de enfield

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Re: The truth about single skin / hybrid tents
« Reply #23 on: 14:22:30, 25/06/18 »

This is what puts me off buying an ultra lightweight tent with a
mesh inner [/color][/font][/size](as well as the cost). What is the point in pinching a few tens of grams on the inner if you are freezing and have to take extra clothes or a warmer bag?


They are maybe a good idea in more benign climates, but for Lake District fell tops, I would say not.



Many simply look at each component in isolation without considering the effects on other parts of the 'system'.


The comfort / practicality of the 'total system' is the overall measure. As you suggest 'robbing Peter to pay Paul' is not always the most efficient, or, cost effective.




Troggy

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Re: The truth about single skin / hybrid tents
« Reply #24 on: 22:26:31, 25/06/18 »
Richard 1905, re the double rainbow, I'll be taking it out on Wednesday to give it a try, although the weather's not likely to give it much of a test! What my thinking was, I'd be able to open the 4 doors a lot more, without freezing as I might do with just mesh. I think the solid liner will help a lot in the cooler weather, it covers both ends and the top, so effectively gives me a solid inner for those areas. I might pass the idea on to Henry Shires and make my fortune...on the other hand!

marmottungsten

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Re: The truth about single skin / hybrid tents
« Reply #25 on: 23:59:09, 25/06/18 »

I think he's maybe referring to condensation on the inner tent? And I think he's wrong that you need mesh to ensure this. I've had various tents over years with non-mesh inners and all of them have handled condensation on the inner tent fine but all of them, including my fairly meshy TN Coshee have had condensation on the inside of the fly - it's unavoidable as far as I can see. Warm wet breath meets cold waterproof sheet = condensation.


The thing about the ventilation - it has another name - it's called "freezing cold draughts" depending on the weather!


No, because the mesh lets moisture out but does not let draughts through...It is the very definition of breathable!


marmottungsten

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Re: The truth about single skin / hybrid tents
« Reply #26 on: 00:19:24, 26/06/18 »
In any tent you are the main source of water vapour, from your breath and sweat. Water vapour molecules are very small so they will pass straight through the weave of un-proofed nylon. When they hit the cold proofed outer flysheet they can't go through it and as it's cold condensation forms. If enough condensation collects it will form drips, if your tent's inner is made of tight weave solid nylon these drips will spread out due the the surface tension and dry quite quickly. On the other hand if your tent has a mesh inner the drips will go through and land on your sleeping bag. So, having solid nylon at least above you is a good idea. Having mesh on the sides of your inner tent will offer less resistance to wind, whether this is a bad or good thing will depend on the ambient temperature.


This is not the case Owen...No-See-Um mesh, used on most modern ultralight US designed tents, has a high resistance to wind penetration but still allows moist vapors like breath through easily (it is highly breathable).  By guying out the fly at the bottom of the tent, via the webbing loops provided for this purpose, a small draught is set up in the gap between the inner tent and the fly, carrying any moist air away before it has a chance to condense on the inner wall of the fly...So you actually stay drier!  You cannot feel any draught once you are in the mesh inner tent, because the mesh does not allow wind through, so you do not get cold inside either.  Using such mesh is not just there to save weight, it is to keep you drier too.

« Last Edit: 00:23:48, 26/06/18 by marmottungsten »

April

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Re: The truth about single skin / hybrid tents
« Reply #27 on: 06:47:07, 26/06/18 »
No, because the mesh lets moisture out but does not let draughts through

No-See-Um mesh, used on most modern ultralight US designed tents, has a high resistance to wind penetration

We have a mixed inner in our US designed tent which uses No-See-Um mesh. There is a big difference in the draught that comes through the mesh as opposed to the solid inner - there was a very cold draught coming through the mesh on Saturday, no draught through the inner. We were 800m up on a mountain in the Lake District. Where do you pitch your tent MT? Below 292m on the Surrey Hills?
"Who would've thought...... you are light and darkness coming through" words by Tim Armstrong

NeilC

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Re: The truth about single skin / hybrid tents
« Reply #28 on: 07:18:17, 26/06/18 »

No, because the mesh lets moisture out but does not let draughts through...It is the very definition of breathable!


Which much be why they make windproof jackets out of no see um mesh...


There's nothing magic about that mesh. It's just mesh that is a bit finer than standard mosquito mesh. They also call it midge netting. It's not a technical standard and just how fine it is varies from maker to maker. It can be very fine or not so fine . The finest examples are more wind resistant but less ventilating, and visa versa. In the US it's common on windows a screen doors.


Plenty of other non-coated fabrics are very breathable too. Most poeple do not get condensation on their tent inners. Most poeple do get it on their fly whether they have a mesh inner or not.


 It's not windproof but merely a bit more resistant that wider mesh. It's just fine enough to stop smaller biting insects. It has better ventilation than denser material but less wind resistance and less ability to trap warmth. That's why tent makers for colder climates only use panels of it above body height to improve ventilation but avoid draughts. It's not a miracle. It has ups and down like all materials.
« Last Edit: 07:28:21, 26/06/18 by NeilC »

alan de enfield

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Re: The truth about single skin / hybrid tents
« Reply #29 on: 07:41:52, 26/06/18 »

Which much be why they make windproof jackets out of no see um mesh...


There's nothing magic about that mesh. It's just mesh that is a bit finer than standard mosquito mesh. They also call it midge netting. It's not a technical standard and just how fine it is varies from maker to maker. It can be very fine or not so fine . The finest examples are more wind resistant but less ventilating, and visa versa. In the US it's common on windows a screen doors.


Plenty of other non-coated fabrics are very breathable too. Most poeple do not get condensation on their tent inners. Most poeple do get it on their fly whether they have a mesh inner or not.


 It's not windproof but merely a bit more resistant that wider mesh. It's just fine enough to stop smaller biting insects. It has better ventilation than denser material but less wind resistance and less ability to trap warmth. That's why tent makers for colder climates only use panels of it above body height to improve ventilation but avoid draughts. It's not a miracle. It has ups and down like all materials.





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