Nikwax and Gore-tex, The infamous saying.

[Crafty]

Has anybody else heard of people saying; "You don't need to use any waterproofing agents on Gore-tex because the material itself is waterproof, it must of been my fault for putting my head inside the bag while I was sleeping." just after they become soaking-wet in their bivi-bag after a storm when they bought a second-hand bivibag they didn't bother to waterproof even though it happens time, after time, after time.
Perhaps it could be them putting their head in their bivi-bag while their sleeping, but how comes it only happens when it rains?

It's a bit of a rant really as I know a bloke who I think will just not accept critisism of his kit no matter what, and that's what he says.

But now I'm in a bit of doubt now though - Is it me who is wrong? I have always thought you had to replace the DWP layer of Gore-tex (or other waterproof-type materials) or other-wise they leak and that there is no breathable material that is waterproof on it's own.
Can I have some opinion of this please as it would be much appreatiated.

 

[Mirius]

You could put waterproofing agents on gore-tex, but unless the gore-tex has broken down I don't see the point. The waterproofing would make it into any other proofed, unbreathable fabric. Sure gore-tex can leak, but if it does then it's time to replace it. I can't see why you'd pay out for a breathable waterproof and then waterproof it. Goretex should not leak, I don't see your point, of course it can be breathable and not leak, that is the point of it after all.

 

[VirusKiller]

My understanding is that Gore-tex and other membrane-based fabrics (e.g. Event) are waterproof. The treatment which needs to be applied regularly is for water repellency on the outer (non-Gore-tex) fabric, because if the outer fabric becomes wetted, the breathable fabric is unable to breathe (due to its outer side being in contact with water).

 

[John Fenna]

If the membrane is clogged with body oils, mud etc then it will not breathe either!
Clean it, proof it and dont let it get punctured!

 

[Crafty]

My understanding is that Gore-tex and other membrane-based fabrics (e.g. Event) are waterproof. The treatment which needs to be applied regularly is for water repellency on the outer (non-Gore-tex) fabric, because if the outer fabric becomes wetted, the breathable fabric is unable to breathe (due to its outer side being in contact with water).

I'm talking about just one layer of Gore-tex, there isn't two layers or anything else. What I mean is that on Gore-tex that is new it has the manufacturer's waterproof solution on it, but after lots of wear that starts to fade, an that's when Nikwax comes in to renew that or otherwise it starts to leak.

 

[VirusKiller]

I may be wrong, but I didn't think that Gore-tex existed without a non-Gore outer. For instance, my British Army bivvy and overtrousers both have Gore-tex inners and a different fabric outer which is bonded to the Gore-tex.

 

[Quark]

As far as I Understand, G-tex (and simelar) are waterproof, but waterwapour can escape thrugh the membrane. But ONLY if it is nok clogged up. AND contitions have to be right too, as in lower water content in the air outside the membrane. I sure temperature difference, windspeed, and other factores will effect the membranes effectiveness too...

The wetness inside a bivibag is often caused by condention.

/Martin

 

[scanker]

Doesn't the ability of goretex to breathe decrease when the outside surface is covered in water - hence more condensation when it rains?

 

[Crafty]

Sorry, that part was a bit of a rant.
I have seen the way this person sleeps and they always have their head out - It's also the same for his jacket but he doesn't have an excuse for that! Also when I say wet I mean that they have had to be evacuated because the sleeping bad was like a sponge and they was on the bridge of hypothermia, when I was warm.
I have inspected it and it doesn't seem to have been punctured and seams seam to be in good condition (sorry about the pun!).

 

[para106]

I think that re-proofing it helps the 'beading' process so that the outer layer doesn't wet out. I reproof mine maybe twice a year to keep them in good nick.

 

[Wink]

The simple answer is that you are both right!

Goretex works by having a plastic coating on a facing material. The coating attracts water to one side (the inside) and moves it to the other (outside), where it evaporates. The plastic membrane may be protected from damage by another layer stuck on to it (as on a British Army bivvy bag). In theory, therefore, the rain should not go through the membrane the wrong way, even if the outer facing fabric is not waterproof at all. However, the vapour will not be able to evaporate if the outer fabric is waterlogged, so it will be no more breathable than a plastic bag, and any build-up of moisture will accumulate. I suspect that this is what is happening to your friend, especially if his sleeping bag is very warm. The sweat alone released during a warm night would be enough to cause a soggy bag. If he breathes ito it as well, it will exacerbate the problem.

If he renews the Durable Water Repellant coating on the outer of the bivvy, the facing fabric will not waterlog so quickly, meaning that the goretex will be breathable for longer, but this will effect the breathability from inside, not the waterproofness from inside! The problem is inherent in all membrane type fabrics, hence the enthusiasm for Ventile and Paramo, which are membrane-free, on this forum. However, as these materials do not work very well for bivvys, the only answer is to make sure that the bivvy is used correctly, and kept clean and re-proofed to maximise its breathability.

Or ditch the bivvy and use a groundsheet and a tarp instead!

 

[Ex Member - Sidney Bounty]

Thanks Wink I am not a fan of Goretex yes we have a few Goretex jackets but in wet weather they soak through in no time and here in Canada being wet and cold do not mix at all I have not seen Ventile or Paramo here but will look today at MEC in Vancouver and see if they have this product I usualy just use a a waterproof poncho in the wet....

 

[spamel]

Stick your goretex item in the tumble drier on a low heat or iron with a low setting on your iron. It relays the fibres correctly and puts the material right again. I don't know the technical jargon, but try it as it does work.

 

[Crafty]

The simple answer is that you are both right!

Goretex works by having a plastic coating on a facing material. The coating attracts water to one side (the inside) and moves it to the other (outside), where it evaporates. The plastic membrane may be protected from damage by another layer stuck on to it (as on a British Army bivvy bag). In theory, therefore, the rain should not go through the membrane the wrong way, even if the outer facing fabric is not waterproof at all. However, the vapour will not be able to evaporate if the outer fabric is waterlogged, so it will be no more breathable than a plastic bag, and any build-up of moisture will accumulate. I suspect that this is what is happening to your friend, especially if his sleeping bag is very warm. The sweat alone released during a warm night would be enough to cause a soggy bag. If he breathes ito it as well, it will exacerbate the problem.

If he renews the Durable Water Repellant coating on the outer of the bivvy, the facing fabric will not waterlog so quickly, meaning that the goretex will be breathable for longer, but this will effect the breathability from inside, not the waterproofness from inside! The problem is inherent in all membrane type fabrics, hence the enthusiasm for Ventile and Paramo, which are membrane-free, on this forum. However, as these materials do not work very well for bivvys, the only answer is to make sure that the bivvy is used correctly, and kept clean and re-proofed to maximise its breathability.

Or ditch the bivvy and use a groundsheet and a tarp instead!

That makes it much clearer, thanks alot!

 

[Crafty]

On the same subject; are there any waterproofing agents he should keep away from (if I manage to do a bit of convincing!) because as you can tell - I'm no expert in this field!

 

[Ex Member - Sidney Bounty]

Seems they do not sell Ventile or Paramo in Canada oh well was worth the try!

guess I keep using the poncho works well enough anyways....

we have done the heat thing and the Nikkie treatment thing with no success in ether one working...

the only plus is that the jackets are warm and with the inner fleece liner they are very comfy warm in the cold...