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Mon Jan 20, 2014 2:27 pm

OK, I've seen several references on here about a vapor barrier in the door. I was putting in new felt and anti rattle grommets, and now I can put the door back together. But what is the vapor barrier. I can kinda get an idea of what it might do by the name, but do you just make up one with whatever?

Mon Jan 20, 2014 2:36 pm

it is a barrier that protects the door panel from moisture. I make a double barrier. One piece that glues onto the outside of the door like stock but I also make an inner piece that forces water to stay inside the door and not exit between the door and the door panel.

Mon Jan 20, 2014 2:38 pm

yes, a sheet of plastic works 6 mil?
There are threads on it, search for details like how its positioned...

Mon Jan 20, 2014 2:42 pm

Yep, it's essentially a plastic sheeting that protects the door card if/when water gets behind the door.

You can easily get your own (Hardware store...I got some 4 or 6mil sheeting, but can't recall off had). You just want to make sure it was strong enough to hold up (not thin like a plastic bag you get from a grocery store).

Anyways, there's a few vids on Youtube out there for putting it on. And a few threads on here as well...the lower section just needs to get tucked into the door so that it drains appropriately. Other than that, hold it up, draw out the template, spray adhesive, and stick it on...then remove the excess with a razor. Then put the door panel on. It's super easy.

Mon Jan 20, 2014 3:12 pm

Be sure to seal the doorpanel clip holes too. Depending on the fabric/material on your panels you'll end up with discoloration at each doorpanel clip in the material.

Tue Jan 21, 2014 6:18 am

thanks for the explanations. I'm wondering about using some wood floor underlayment that is supposed to be a moisture barrier for the wood. It's a thin sheet of foam like plastic. Might cut the noise a bit too. I've got some extra of that lying around here after putting in a floor.

Tue Jan 21, 2014 10:13 am

I suppose it depends on how thick it is, and if it can take the heat/cold/wet that a car gets exposed to? I'm assuming so...right?

If it's too thick, it may not allow for the clips to catch when putting the door panels back on. But if you have it lying around...why not give it a try first and see.

Good luck,

Tue May 02, 2017 6:37 am

Realize this thread is somewhat older but hope someone is watching.

For the second layer of vapor barrier (to protect the panel itself), what is the thought about using spray on sealer instead of a second layer of plastic sheeting?
Seems like the sealer might be a good idea to avoid the plastic deteriorating, splitting, e.g.
I've used the sealer on other items and it seems to work well, just not sure the panel board will accept the sealer without warping or ???

Tue May 02, 2017 8:38 am

I used 1/8" ABS plastic for my door panels... good thing, I've taken the panels off at least 5 times since doing it.

One sheet should be fine... properly positioned so water runs away from the door panel. Shellac will make the door panel impervious to any water if that will make you feel better

Tue May 02, 2017 8:53 am

The problem with a spray waterproofing is that you have to do both sides, or the wood will cup in high humidity. Best to let it breath, and use the vapor barrier of plastic. Understand that water WILL get into the door. The window scrapers are not waterproof, even when new. So the plastic is intended direct the water INTO the door cavity, and away from the porous wood door card. The door has drains at the bottom for this water to eventually exit the vehicle. They have to be kept free of dirt and debris, or it becomes a rust magnet. A few dabs of glue along the perimeter and in a few other points in the door frame is enough to keep it in place. I've seen some with extra care around the door card clip holes, which would keep water from wicking to the card there.

Tue May 02, 2017 9:47 am

Contractor bags are 3 mil. Not thick enough?

Tue May 02, 2017 5:35 pm

stolen image from ghia girl .com but this is how it should be set out, making sure it tuck in to the door on the lower end to let water or moisture drip into the bottom of the door and out trough the drain holes, i used concrete underlay plastic which is about 2mm thick. its enough any thicker wont make nuch of a difference as its just to stop moisture

Wed May 03, 2017 5:17 am

I have not replaced ripped vapor barriers on my Ghia yet as it needs new panels anyway... But I have used contact paper+ dynaliner on my 1981 BMW which is okay but ended up too thick for a door card to look right. Contact paper from homedepot is peel and stick, which made it very easy to deal with.

I am going to replace the contact paper with a roll of BMW vapor barrier to do it properly. I am planning to do the same for the Ghia. Not the cheapest (approx $30 for a roll that does both sides) but its OEM, peel and stick and should last many years. No need for messy butyl tape or glue.

Max

Thu May 04, 2017 5:33 am

Best suggestion I've read for a barrier is a shower curtain. :)

Thu May 04, 2017 7:16 am

runamoc wrote: Best suggestion I've read for a barrier is a shower curtain. :)
I learned three things this morning ...

- a shower curtain liner would make great material to use as a vapor barrier in car doors

- apparently there is a rather large selection of Volkswagen Beetle and Microbus themed shower curtains available out there!

- there appears to be a golden opportunity out there for someone who wants to clean up by offering Volkswagen Karmann Ghia themed shower curtains for sale to the discriminating Volkswagen enthusiast. :)

Thanks, for the suggestion, runamoc - it's a great one.

Thu May 04, 2017 8:16 am

Once the door is put back together, the vapor barrier will never again be seen by human eyes until the next time the door is taken apart.

Thu May 04, 2017 12:32 pm

runamoc wrote: Best suggestion I've read for a barrier is a shower curtain. :)

Even better, Buy a new one to please the missus ,repurpose the old.

I have found double sided carpet tape works best for adhering the plastic to the door.

Fri May 05, 2017 11:43 pm

scottyrocks wrote: Once the door is put back together, the vapor barrier will never again be seen by human eyes until the next time the door is taken apart. I installed a wiper motor signed by Everett.
Sometimes you do things just for fun.
What's fun for one person... might not be for another.
Hobbies are supposed to be fun, right?

Sat May 06, 2017 2:43 am

Here's what we used. No problems so far, but then again, the closest that the car has been to water is the hose bib that's 50' from where we are working on her :P

TRM Visqueen - 6.0mil
https://www.amazon.com/gp/aw/d/B00KOOF5W0/ref=mp_s...ier+61025c

3M 08578 1" Caulk Strip (Black)
https://www.amazon.com/gp/aw/d/B000PEZ1L4/ref=mp_s...plSrch[/b]

Sat May 06, 2017 7:55 am

easy e wrote: scottyrocks wrote: Once the door is put back together, the vapor barrier will never again be seen by human eyes until the next time the door is taken apart. I installed a wiper motor signed by Everett.
Sometimes you do things just for fun.
What's fun for one person... might not be for another.
Hobbies are supposed to be fun, right?

Wasn't criticizing - just stating the (incredibly) obvious. :)