Silicon or PU coated Fly

[climo]

Which is better?
I've got my eye on a quality Exped tent with a 40D material, 1500mm water column PU coated fly. In my mind that's nowhere near as waterproof as a silicon coated Hilleberg fly at 5000mm but am I right?

[foxyrider]

The numbers speak for themselves regardless of material. 1500 is what i'd expect to find on a festival tent for summer use, 5000 is 3 season - I personally wouldn't buy with less than 5000 fly for serious camping.

My current tent has 5000 fly, 3000 inner and 5000 ground tub and even at that wet has been known to get through.

[pjclinch]

Which is better?
I've got my eye on a quality Exped tent with a 40D material, 1500mm water column PU coated fly. In my mind that's nowhere near as waterproof as a silicon coated Hilleberg fly at 5000mm but am I right?

You need to decide on the point where "better" simply costs you more than "good enough".

In terms of waterproofing there really isn't an obvious "better" between silicone elastomers and PU coats: it's really down to how much you put on to what base and do you do it well enough. Hydrostatic head is a good measure of waterproofing, but effectively watererproof comes in at about 1000 mm. More is notionally better because these numbers will probably degrade over time, but if you're only using a tent for a couple of weekends a year and it tends to be good weather that's a bit academic.

Silicone has a couple of major advantages over PU for a fly. First, applying a PU coat is done as a molten dip and this heat-ages the base fabric, making it considerably weaker in terms of tear strngth. Silicone coats also help filter UV so there is less damage done to the tent out in the sun over time. The disadvantages come with silicone coats being very slippery, so they are more difficult to handle for construction and also to apply seam taping. A popular compromise is silicone on the outside and PU inside, but that still means a weaker fabric and if you can be bothered to coat the seams in a sealer (few pounds and half an hour) you don't need seam tape, and taping tends to weaken things as well, plus adds to the weight and bulk. A well made seam won't necessarily leak in any case (neither of my Hilles have had any extra treatment, neither leak). Silicone is more expensive too.

Another thing is polyester vs. nylon. Nylon tends to be a bit stronger weight-for-weight but it's less stable and degrades more readily than polyester, even with a silicone coat. So if it'll be parked out in the sun for weeks on end then polyester may well be a better choice.

But we get back to "better" vs. "good enough". If you have very deep pockets no reason not to go for "better", but most of us don't and have to consider boring old "value for money". Given a straight choice between a Hubba Hubbba and a Rogen (both similar size, weight and layout) I'd take the Rogen, and silicone fly both sides would be part of that choice. But look at the price, and... we have a Hubba Hubba.

Pete.

[pjclinch]

My current tent has 5000 fly, 3000 inner and 5000 ground tub and even at that wet has been known to get through.

If the inner has a 3m hydrostatic head it won't be very breathable, which is a bit of an own-goal when it comes to staying dry. An inner benefits from a light DWR to shed droplets but really doesn't need more than that.

Rain or groundwater won't get through a 5m HH fabric, but it will easily get around it, usually in moist air. When it cools down, moist air tends to dump excess as condensation, and that's how you get most water inside waterproof tents. The other "popular" method is water that comes in with occupants when they get in and out in the rain.

Pete.

[PH]

The rare times I've got wet in a tent it hasn't had anything to do with how waterproof the fabric was. As highlighted in another current thread, wetting out is a more likely problem, there may be no water coming through, but there's so much sitting on it that condensation increases and the added weight makes transferring it to the inner probable. In my limited experience, a silicon fly retains its water repellency better than a PU one. There was a thread on here a while back when someone was convinced their tent was leaking, then they tested it and found that wasn't the case.
All else being equal I'd choose a silicon fly and be prepared to spend a bit more to have it, but it isn't that high on the list and I wouldn't reject a PU one if I otherwise preferred the tent.

[foxyrider]

My current tent has 5000 fly, 3000 inner and 5000 ground tub and even at that wet has been known to get through.

If the inner has a 3m hydrostatic head it won't be very breathable, which is a bit of an own-goal when it comes to staying dry. An inner benefits from a light DWR to shed droplets but really doesn't need more than that.

Which is why it has good ventilation from two end 'windows and a large inner door.

The forerunner to this tent had a 5m inner which was a bit of overkill! I also woke one morning in Switzerland to find myself actually floating as the deep 10m tub really did do its job. Of course I got wet getting out of the tent but all my gear stayed dry.

[pjclinch]

My current tent has 5000 fly, 3000 inner and 5000 ground tub and even at that wet has been known to get through.

If the inner has a 3m hydrostatic head it won't be very breathable, which is a bit of an own-goal when it comes to staying dry. An inner benefits from a light DWR to shed droplets but really doesn't need more than that.

Which is why it has good ventilation from two end 'windows and a large inner door.

The forerunner to this tent had a 5m inner which was a bit of overkill! I also woke one morning in Switzerland to find myself actually floating as the deep 10m tub really did do its job. Of course I got wet getting out of the tent but all my gear stayed dry.

I've had the inner floating on my Spacepacker a couple of times (once on melting snow in Norway, once in rising groundwater in Glencoe) and aside from the condensation on the floor (all that cold water underneath makes for a great condensing surface) everything inside was dry, and while I'm not sure what the HH rating is I'd be very surprised if a tent that old had anything like as much as 5K, never mind 10. That's what bathtub groundsheets are for, and enough remains enough. Heavy duty waterproofing on the inner walls is just wasted effort, and if you have to keep all the vents and door open just to avoid lots of interior condensation then that's a shame if you want to maximise warmth...

I've never seen anyone touting this "feature" before, and I think there's a reason for that...

Pete.

[climo]

Exped tent are generally considered to be very good tents. Fly material is most models is PU coated and 1500mm water column is standard on almost all Exped tent flys and groundsheets are 5000.
Go figure.

[foxyrider]

If the inner has a 3m hydrostatic head it won't be very breathable, which is a bit of an own-goal when it comes to staying dry. An inner benefits from a light DWR to shed droplets but really doesn't need more than that.

Which is why it has good ventilation from two end 'windows and a large inner door.

The forerunner to this tent had a 5m inner which was a bit of overkill! I also woke one morning in Switzerland to find myself actually floating as the deep 10m tub really did do its job. Of course I got wet getting out of the tent but all my gear stayed dry.

I've had the inner floating on my Spacepacker a couple of times (once on melting snow in Norway, once in rising groundwater in Glencoe) and aside from the condensation on the floor (all that cold water underneath makes for a great condensing surface) everything inside was dry, and while I'm not sure what the HH rating is I'd be very surprised if a tent that old had anything like as much as 5K, never mind 10. That's what bathtub groundsheets are for, and enough remains enough. Heavy duty waterproofing on the inner walls is just wasted effort, and if you have to keep all the vents and door open just to avoid lots of interior condensation then that's a shame if you want to maximise warmth...

I've never seen anyone touting this "feature" before, and I think there's a reason for that...

Pete.

The windows are not open/closed, they just are mesh windows behind vents in the fly. Not 'touting' anything just describing the tent.

[pjclinch]

Not 'touting' anything just describing the tent.

What I mean by "touting" is marketing departments pointing out their tent is better with a justification that it has an extra layer of waterproofing. Like I say, I don't see anyone doing that, though I'm curious as to who is actually making tents like this, and given the number of happy punters finding a light DWR on the inner quite sufficient, why they bother?

Pete.

[foxyrider]

Not 'touting' anything just describing the tent.

What I mean by "touting" is marketing departments pointing out their tent is better with a justification that it has an extra layer of waterproofing. Like I say, I don't see anyone doing that, though I'm curious as to who is actually making tents like this, and given the number of happy punters finding a light DWR on the inner quite sufficient, why they bother?

Pete.

The tents are both from Vaude, made in Tettnang, Baden

[crazydave789]

my very old north face tadpole is silicone and has outlasted several other tents.

I refresh knackered PU tents by siliconing them. I'd rather they didn't use seam tape at all,

[pjclinch]

The tents are both from Vaude, made in Tettnang, Baden

A quick look at the current models on their web site don't suggest any HH figures for inner tents. e.g. the top of the line £1500 Power Sphaerio says of its materials: Flysheet: 88% Polyamide, 12% Polyester; 30/40 D Ripstop both sides Silicone coated 3.000 mm; Inner tent: 100% Polyamide; 40 D Ripstop; Floor: 100% Polyamide; 40 D Ripstop Thermoplastic Polyurethane laminated 10.000 mm.

The £700 Ferret XP ("suitable for winter") says: Flysheet: 100% Polyamide; 40 D Ripstop both sides Silicone coated 3.000 mm; Inner tent: 100% Polyamide; 40 D Ripstop; Floor: 100% Polyamide; 40 D Ripstop Thermoplastic Polyurethane laminated 10.000 mm.

and similar for others I looked at.

So my immediate guess is you're simply mistaken, and that's not a problem in itself. I'm just trying to make sure misunderstandings don't get passed on as buying advice.

Pete.

[foxyrider]

The tents are both from Vaude, made in Tettnang, Baden

A quick look at the current models on their web site don't suggest any HH figures for inner tents. e.g. the top of the line £1500 Power Sphaerio says of its materials: Flysheet: 88% Polyamide, 12% Polyester; 30/40 D Ripstop both sides Silicone coated 3.000 mm; Inner tent: 100% Polyamide; 40 D Ripstop; Floor: 100% Polyamide; 40 D Ripstop Thermoplastic Polyurethane laminated 10.000 mm.

The £700 Ferret XP ("suitable for winter") says: Flysheet: 100% Polyamide; 40 D Ripstop both sides Silicone coated 3.000 mm; Inner tent: 100% Polyamide; 40 D Ripstop; Floor: 100% Polyamide; 40 D Ripstop Thermoplastic Polyurethane laminated 10.000 mm.

and similar for others I looked at.

So my immediate guess is you're simply mistaken, and that's not a problem in itself. I'm just trying to make sure misunderstandings don't get passed on as buying advice.

Pete.

Firstly i'm not mistaken, the information was with the tents when new. Buying advice? Whilst I would happily promote the Vaude tents, I haven't done any of the Hille etc willy waving of others on this thread, just stated my experience of using these tents.

And neither of my tents are the models you quote. Just because they don't currently quote something on their website doesn't mean it's not true. Not even sure they had a website when I got the first tent!

For what it's worth the tents are a Taurus UL from @ 2002 and a Power Lizard SU from 2013.

[pjclinch]

Firstly i'm not mistaken, the information was with the tents when new. Buying advice? Whilst I would happily promote the Vaude tents, I haven't done any of the Hille etc willy waving of others on this thread, just stated my experience of using these tents.

And neither of my tents are the models you quote. Just because they don't currently quote something on their website doesn't mean it's not true. Not even sure they had a website when I got the first tent!

For what it's worth the tents are a Taurus UL from @ 2002 and a Power Lizard SU from 2013.

What I'm saying isn't true is that it's clearly a great idea to have a formally waterproof inner tent. If vauDe did think that 5 and 16 years ago they don't seem to think it now (current models of those tents don't quote a waterproof inner), and again I suspect you're simply mistaken. Drop them a line and ask. I've a few friends with vauDe tents and nothing about the inners has looked any different to Brand X's as far as overall construction goes.

They did have a website when you got your first tent, you'll find it archived at the WayBackMachine. Functionality is generally compromised, so it's tricky to see if vauDe really were waterproofing their inners back then.

Pete.