Campervan Vapour Barrier ? Yes Or No

[Oldrat]

For those that have done a conversion or have purchased a campervan conversion.

How many of you have a vapour barrier and how many chose NOT to have a barrier installed.

Ie a plastic (poss similar to bubble wrap?) layer on top of the insulation layer but behind the interior panel

I’ve heard arguments for and against, but would like to
a) weigh up the numbers
b) would welcome a professional opinion


Thanks

 

[Pete C]

Can you define what you mean by vapour barrier, and where it would go ?

Pete

 

[Oldrat]

First post edited Pete

 

[Markymark]

Our van which was professionally converted and has limited insulation and therefore little or no vapour barrier. Hasn’t been an issue and we use it all year round including going to the alps skiing.

 

[Oldrat]

156 views and hardly a dickie bird.


Are vapour barriers the new elephant in the room??
Good or bad
yes or no

??

 

[Planestoner]

We use them on commercial aircraft (predominantly at floor level) but I hadn’t really considered fitting any for my conversion. There’s a door slam relief behind the near side wheel arch isn’t there, if so wouldn’t it cause an issue with the pressure relief when closing a cab door?

 

[dubber36]

Surely a non-breathable vapour barrier like polythene would trap condensation in the van?

We use Tyvek or similar products in buildings due to lack of through ventilation, so I can't see a tin box being any different.

 

[Peatey]

I dont know of a camper conversion with a vapour barrier but that doesn't mean it doesn't work. Mine certainly hasn't and i don't have any problems.
If i was going to install one i would only put a breathable material and stay well away from any plastic product.

 

[Oldrat]

Thanks for those who have answered, useful feedback.
It’s for my new LWB crafter, with superhigh roof, so yep, a lot of panel area.

We will have two decent roof fans, so we can have an in / out flow when cooking etc.

I’m still after your thoughts and feedback please so keep them coming

 

[Oldrat]

For those who are thinking of insulating a van, you’d do a lot worse than watch this guy, Greg Virgoe.
He is a heating and ventilation system designer for commercial buildings and he puts his expertise into his own self build. He has documented his entire Merc Sprinter campervan conversion on YouTube which runs to a set of 64 (!!!) videos.


He is a very handy and clever guy, and his vids are textbook for any self builder.

I’ve just revisited Greg’s videos to find his take on my Q, and it seems that a vapour barrier is necessary to prevent your van rotting from the inside

 

[DXX]

For those who are thinking of insulating a van, you’d do a lot worse than watch this guy, Greg Virgoe.
He is a heating and ventilation system designer for commercial buildings and he puts his expertise into his own self build. He has documented his entire Merc Sprinter campervan conversion on YouTube which runs to a set of 64 (!!!) videos.


He is a very handy and clever guy, and his vids are textbook for any self builder.

I’ve just revisited Greg’s videos to find his take on my Q, and it seems that a vapour barrier is necessary to prevent your van rotting from the inside

I think our diesel vans will be banned from the road long before they rot out.
I’m about to install some vapour barrier in a house, it has to be thoroughly sealed at all penetrations and joints to be effective.

 

[Oldrat]

That’s another way of looking at it

however who knows what the future holds—- perhaps folk will find out the real lifetime costs of EVs and that modern diesels are actually more efficient than many realise—— perhaps there will be a growth
Business for installing electric motors in our existing vehicles (already happening at the mo)

Either way, for a relatively low cost/effort it’s worth doing

 

[Bryn23]

Vapour barrier in a van is a no for me,

I know how important is is in a house, I am also a trained residential drafter.

but a van and a house are two different animals and have different ventilation set ups, depending on the house design and cladding, semi breathable va[our barriers may be required.

using a vapour barrier in a van will cause issues in the long term.

 

[Oldrat]

Thanks for that Bryn, I appreciate your input.

So- Would it make any difference to your view if the van were used as a long term habitation, say with with regular daily cooking inside.

My T6 is used, like most on here I guess, as a holiday/occasional ‘residence’, but I’ll be away for much longer in the bigger van (or I hope so!) and making use of it all year around, so spending prolonged time creating moisture.

It will have a decent ventilation system but I am concerned about what will happen as there is bound to be some moisture in the air that is likely to hang around and condense on the bodywork.

Greg Virgoe makes a really logical case for a moisture barrier, but whilst I’ve heard views against, I’ve not yet been able to understand the downsides.
Thoughts and experiences welcomed please

 

[Skyliner33]

Im no expert on this subject but here are my thoughts.
Firstly are you going to be able to create a perfect airtight seal all around for the vapour barrier? My guess from my experience of lining my van is no.

If you are able to create a perfect seal then the air you will be trapping inside this seal will contain moisture.
Secondly if its not a perfect seal then water vapour will find its way in, granted slower, but also when it is in there it will also take longer to get out, potentially giving the vapour more time to condense. Also as there is a vapour barrier that trapped moisture will take longer to evaporate and dry out.

 

[Whit]

That’s another way of looking at it

however who knows what the future holds—- perhaps folk will find out the real lifetime costs of EVs and that modern diesels are actually more efficient than many realise—— perhaps there will be a growth
Business for installing electric motors in our existing vehicles (already happening at the mo)

Either way, for a relatively low cost/effort it’s worth doing

Hi Oldrat, having just bought a 9 month old T6, I'm quite depressed about the thought of it being banned! But, am interested in the thought of Electric Engine conversion, could be life after death! is there anywhere on the Forum or WWW with more info about this?

 

[Oldrat]

Hi Whit
http://londonelectriccars.com/

[URL="https://www.electricclassiccars.co.uk/"]Welcome to Electric Classic Cars[/URL]
http://londonelectriccars.com/
There’s a lot of companies springing up, but very expensive.
Google - Electric car conversion
http://londonelectriccars.com/

 

[DXX]

In my opinion the condensation on the interior of the body shell with evaporate and escape on a warm day if you ventilate the van.
Problems may occur if a damp van is stored for long periods in a cold environment without adequate ventilation / heating, but the same applies for houses, caravans etc.
Use it on a regular basis and I don’t foresee an issue. RVs have survived the pre-membrane years without many issues.
I live in my SWB T6 for weeks at a time and cook everyday, so far I haven’t picked any mushrooms off the body lining.

 

[Oldrat]

That real world experience is really useful, thanks

 

[Stay Frosty]

You need to ventilate or failing that run a dehumidifier regularly during prolonged occupancy of a camper van.v

Sealing a medium sized camper van would be similar to wearing polythene clothes as it's our personal respiration and perspiration that produces most of the condensation.