Moisture barrier in doors, yes or no?

CTD

CTD

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Hi everyone,

I am done cleaning up the insides of the doors of my coupe. I have installed dynamat on the inside of the entire outer shell and I am now debating if I should re-install the new moisture barrier or something else. I have never experienced the car with the moisture barrier in place so I am scared it will vibrate or create noises. I am perfectly aware of the benefits to protect the interior from moisture intrusion but my coupe will never see bad weather anymore anyway.

I could install it and experience myself if it is any good but it leaves such a mess (glue residue).

What would you do? Or do you have another suggestion? Let me know.
 
YES, install moisture barriers to keep from deteriorating the back of the door panels. just be sure that your door drains are clear and the dynamat doesn't block them. as far as the glue goes, apply with a thin / fine strip. +1 on the pieces from @alprada70
 
I replaced mine in the Pre-alprada70 era so got some sheet plastic from HD , think 3mil and cut it to size and held it in place with 3M strip caulk so I can remove it if I need to. No glue. I also applied a thin coat of Fluid Film to the bottom of the inside of the doors before sealing it up.
 
I got the material from W&N. Cut it using my old doorpanels as a template.
Pretty thick stuff. But extremely sticky and because of that I am hesitant of installing it.
 
I used the parts from @alprada70, the sheets are all laser cut and fit perfectly with very strong adhesive already applied. I did mess one up when installing and decided to use heavy duty plastic vapor barrier material that I had a roll of. That is a cheap effective solution too.
 
bavbob said:
held it in place with 3M strip caulk
Click to expand...
I use this on all non permanent films. It makes it much easier to revisit the area if you have to.


Bonus Pro Tip!: it is also great for holding bolts/washers/nuts in place or in sockets.
 
For decades I have used hardware store "contact paper," self-adhesive, easy cutting and shaping, looks just like Betty Crocker's shelves.
 
Install them, yes. You don't plan to drive in inclement weather, but life doesn't always go as planned.
 
Yes, vapor barrier was installed during the original assembly factory. It's always necessary to have the vapor barrier. Even if you will "never ever" drive in in bad weather until you inevitable do.

Contrary to the popular mythos of these BMW & water be strictly forbidden or the Evil Rust Goblin will eat your Coupe. Ritual cleaning of the sand & very small rocks from the inner fender shelves, lower inner front fender & rocker cover drains should be part of everyone's maintenance plan. Strongly advise Lokari Front Fender Liners. At least annually, remove the Rocker Panel Covers & clean the inside of them & the gritty film on the car. @Stevehose wrote about this several years ago about all of this, it may be in the FAQ DIY section.
 
I purchased a roll of self adhesive carpet runner which I bought in a role somewhere (big box home improvement store maybe). It's the stuff they layout on carpets in a new house to create a path to walk on. It's tacky but not super sticky so I can apply it to the door and it sticks then I trim off the excess.
 
I used the ones from @alprada70, very well done product works great…
IMG_6809.jpeg
 
I think that it is interesting,
a barrier is a barrier, but you must place it on the door sheet metal not on the panels, sound improvement too, yes
but I have not found the right material,
to protect the door panels you do not need these, it is better to apply a coat of latex to the door panel and virtually seal it
 
deQuincey said:
a barrier is a barrier, but you must place it on the door sheet metal not on the panels,
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As long as you have a sheet of plastic blocking any moisture inside the door from the panel, how does the panel know whether that plastic is adhered to the door or to the panel? Why wouldn't it serve equally well as a barrier if it was stuck to the panel?

deQuincey said:
it is better to apply a coat of latex to the door panel and virtually seal it
Click to expand...

I have used a few coatings of Thompsons Water Seal to make the fiberboard more water-resistant.
 
jmackro said:
As long as you have a sheet of plastic blocking any moisture inside the door from the panel, how does the panel know whether that plastic is adhered to the door or to the panel? Why wouldn't it serve equally well as a barrier if it was stuck to the panel?



I have used a few coatings of Thompsons Water Seal to make the fiberboard more water-resistant.
Click to expand...
Well said Jay.
 
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