Vapor Barriers

[jsoto]

Everytime I open up the door panel , whether it's to replace a window reg, etc - I always replace the vapor barrier and use good butyl.

I must be slipping as the car was out of the garage in the nonstop 36+ hr rain we had and both front and rear DS is wet. Front more / rear, just primarily along where the door meets the body.

I always use a new VB as I ain't got the time to fug with repurposing the VB. In the last 28 months, I def have opened up these 2 panels.

[EODguy]

What do you think about using tyvek vapor barrier? Used in pretty much all new construction these days and has much better breathability. Issues, problems?

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[andrewwynn]

The water where you describe is usually from the moon roof drain being overwhelmed. More often than not it doesn't even need fixing just less rain.

If you have to leave your car out in a major storm 4 pieces of packing tape would probably prevent a recurrence


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[jsoto]

Re: tyveck. No. As to some degree, aside from the material/butyl on sealing it, I would think the material is to mitigate some noise ?


I actually don't check the floorboard when it rains. But when it's predicted for a 24-36 hr soaker, I do make it a bi yearly process to keep it in the elements to see if there is water.

I'm not correlating the roof drain lines though - it was not on my radar, it would ~overflow~...I'll have to put on my thinking cap, but in my mind, no extra amount of overflow should lead to water in the floorboard.

Once that floorboard get wet, it takes +++++ to get it dry. I can't imagine that overflow we speak of is acceptable...

[80stech]

And Tyvek is NOT a vapor barrier exactly because it has some breath-ability.

[andrewwynn]

Tyvek is an air/moisture (liquid water) barrier similar to gortex in clothes will let vapor through but not liquid water. It would let vapor through but keep liquid water out, it would probably do a fine job in that it's slightly permeable and would let all moisture out during dry phases. It wouldn't be a sound insulation at all through.

I have not had any problem using a long razor knife to cut through the original goo adhesive to reuse both the vapor barrier and adhesive when going into my car doors to work.


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[andrewwynn]

Originally Posted by jsoto

I actually don't check the floorboard when it rains. But when it's predicted for a 24-36 hr soaker, I do make it a bi yearly process to keep it in the elements to see if there is water.



I'm not correlating the roof drain lines though - it was not on my radar, it would ~overflow~...I'll have to put on my thinking cap, but in my mind, no extra amount of overflow should lead to water in the floorboard.



Once that floorboard get wet, it takes +++++ to get it dry. I can't imagine that overflow we speak of is acceptable...

I just know that at least a couple times a year somebody reports mystery water in the foot well and it's almost always determined to be the roof drains. I don't know how the water works it's way there but probably just inside the a pillar trim. I would pull the trim and check for moisture. Then I would blow out the drain tube as there is likely some debris that is slowing the drain.

Very unlikely the water ingress came through the door. I once drove through a flood where the water was almost to my door handle outside and water barely squeaked through.

If not the roof drains it would most likely be a windshield seal.

You could remove the a pillar trim and pour a bunch of water on the roof to confirm.

[jsoto]

Those post are for clogged drains. I wash my cars religiously enough that when I pull the car in, I see telltale spots of water from the drain lines. My lines are fine in that respect.

Driving through a high water table is different than water ingress from constant water on a 24-36 hr period though

[andrewwynn]

Oh: to dry your floor take advantage of simple laws of physics. Change the partial pressure of the h2o with heat.

If you live in a got climate park the car in the hot sun get the inside up to 150° or so then crack the windows to vent the relatively humid air, repeat until dry.

If cooler climate use a space heater, just aim the output at the floor and try to get the floor carpet to to at least 150°F use an IR thermometer.

You can try to get the temp up closer to boiling (212) and every bit of water will vaporize but it's a lot easier to just say set up the heater outside the door on a stool pointing at the floor, get the carpet up to 150-180 and it will be bone dry in half a day. Plastics like the trim and carpet can handle about 320° before they start getting soft. Hot air gun is way too hot. Ceramic heater is good, quartz heater could work ok if you add a small fan to prevent overheating and monitor with IR thermometer.


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[andrewwynn]

Originally Posted by jsoto

Those post are for clogged drains. I was my cars religiously enough that when I pull the car in, I see telltale spots of water from the drain lines. My lines are fine in that respect.

Driving through a high water table is different than water ingress from constant water on a 24-36 hr period though

There is a recent thread from somebody who's car was outside during a torrential rain and the rooted out cause was the roof drains weren't big enough to handle the amount of rain. I believe nose down parking was also part of the problem.

(The drains were not clogged: it was determined that they just got overwhelmed by the quantity of rain)

Constant water no matter how fast will never compete with "under water". Did you check the door seal? If there is a compromised seal of course that could also be the source of your ingress.

Using some dry paper towel can you trace the water source? Eg is the carpet wet at the door threshold? Is the door card wet?


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