The Stovebolt Site Forums The Shop Area General Truck Talk Condensation?

Has anyone dealt with substantial amounts of condensation on the interior roof portion of the cab?

I was wondering if there was an anti-condensate coating that could be applied to the metal to prevent the build up of water. In the PNW anytime the truck is parked outside during inclemental weather she drips, drips, drips...

Even my COE parked in the carport fully undercover collects enough moisture to soak a rag through in minutes.

Last year I put a new headliner in my '53 only to have it deform within about two months. It's in the garbage and now my head gets wet. Other than wear a hat, any ideas?

Thanks, Jeff

You could always move out of the wet lands and to the mid-west Jeff, but you knew some *
was gonna say that, dint you!

But seriously, I'm sure your aware that when the saturated air hits a surface that's colder
than it's dew point you will have condensation. I don't know of any "anti" condensation
coating but back on the farm we used a light bulb to warm the chicks in the chicken coop.
I've also hung a 150w bulb and a blanket inside the engine compartment to keep a little
heat in the block over night.

If you can hang a bulb in your cab and bring the temp up a few degrees, that is, above the
dew point of the atmosphere it might help get rid of the drip.
Denny Graham
Sandwich, IL


If you

This is what I assumed the original felt paper on the roof was for. I thought it provided an insulation barrier.

Now this is just my opinion mind you, but I though that felt
paper in the roof was just a damper to kill the drumming effect
of the roof, something like a bass drum tone dampener.

Denny Graham

Ahh condensation, my old nemesis.

Here in the PNW, the amount of condensation is ludicrous.

My experience, is that putting the tar paper in helps a little. After all, what you want, is to keep the roof from getting below the dew point, as it's being cooled from outside the truck, insulation helps. If you use insulation though, you'd better use something that won't collect moisture, don't use fibreglass for instance! At some point, the roof will still get below the dew point, and then the condensation forms on the insulation if it's exposed, or head liner, or both.

So, what I've found most effective, is to keep the humidity in the truck down, driving the truck every day does this, as the heater (especially the fresh air) dries the truck out. Now, I understand that not everybody drives every day. When I'm not around, and my truck is sitting in the car port all lonesome, I leave a small (500watt) electric radiator in the cab. Now, it's not on all the time! I just use an outdoor timer, and have the electric rad and the block heater come on at the same time, for a few hours, just before dawn, and just before dusk. The block heater is nice too, as it keeps the darn block from getting all rusty from condensation too, as its warmed up. Having a block heater is great for winter starting, but the best part is, if you leave the truck plugged in for a few hours before you start it, the intake manifold and carb get warm, and won't freeze up as often. Where I live, any time the temperature gets low, and the humidity gets high (all winter!) the carb will freeze up a few minutes after the truck starts.

In my last truck, I had an old in car heater under the dash, so didn't need to use the electric radiator. I haven't found one "cool" enough looking for the panel truck yet, and as I'm not often gone, I use the portable heater.

Nothing is as un cool as driving around having the roof drip on your head. Ugh.

Maybe get a small fan to run inside the truck. Plug it in and let it run when you park it. That will keep it dry.

Just what I need, something to keep the mice nice and cozy!

Don't park it, just keep driving. Other than parking it inside I can't think of anything that would stop all moisture. Air movement and a heat source (maybe a drop light) would help.

i put this stuff in my boat to keep the closed cabin from getting mildew. it absorbs moisture. it will keep 200ft3 (6'x6'x6' cube) space dry. maybe it will work for you in this application.

damprid

When they were first inventing the small fiberglass travel trailers years ago, the inside was just plain fiberglass. With the first trials they found that there were condensation troubles in the cool weather. They ended up using a thin rubber insulating material that NASA used. That solved the problem.

My 38 Chev sedan has the felt on all the inside surfaces. I think it is there to combat both condensation and noise.

Just a thought, what if you where to paint the roof with a bed liner material that would act as a thermal break? It would be hidden under the head liner and may also dampen some sound.

I think the bedliner idea is worth looking into. Maybe some of the self adhesive souundmat/insulation would work too. I think the paper headliner only compounds the problem by wicking the moisture. Just like in your home, you need insulation and a vapor barrier to keep the moisture out. Just my two cents.

Insulate the roof and the glass will cool fastest and collect the condensate.

I coated the roof with a rubbverised undercoating & installed a PVC headliner from Classic Parts

I had a condensation problem on my last boat, 44' Steel trawler, and I found that leaving the windows open so that there was natural ventilation kept the condenstaion at bay. The problem I had only happened in the winter and I wasn't living on it so it wasn't a problem with a cold boat as all systems were winterized anyway.

So maybe the simplest solution would be to leave the side windows open a little to maintian even temps.Larry

The only solution is to decrease the amount of moisture in the air, or increase the temperature of the air-surface interface (anywhere where the air touches any surface). Air flow across the surfaces often eliminates or ameliorates the condensation problem.

"Condensation occurs when moist air comes into contact with cool surfaces, such as glass/metal. This type of condensation appears when the dew point in the air is higher than the temperature of the glass."

"Whenever there is excess humidity, it manifests itself in the form of condensation on the coldest area/surface, which is normally the windows or the walls. The warmer the air, the more moisture it will retain, so when air in your home/cab comes in contact with the colder glass/wall/roof surface, it is subsequently cooled and moisture is released in the form of condensation on the glass."

jointsmith posted the truth. Folks in high humidity environments have few options (unless you can raise the heat of the surface, as Denny suggested earlier), or unless you can use a humidifier.

I remember visiting Williamsburg, VA many years ago. The old buildings had single-pane windows and big pools of water outside every building: high-humidity outside air, air-conditioned old buildings with cold single-paned glass. When we got to our cars, and turned on the air-conditioning, we also had to turn on the windshield wipers (condensation forming on the outside of the windshield), The car's air-conditioning system evaporator take a workout.

I glued a foil faced bubble wrap material to the roof of my cab. I found it at home depot. It would seem if you cracked the windows the air temps would equalize and there should be no condensate form. I have also seen a fan you mount in the window and is solar powered.

Never thought I'd have to get out the dictionary to figure out a post here on the 'bolt....

ameliorate: to make better or more tolerable.

Well, it could have been worse. It could have exacerbated the situation. My Mom taught me those words.

Ya just had to get me goin’ dint cha Hot Rod John!!!
That’s not yo mama Tim, that’s the professor comin’ out in ya.

Your Dictionary
Ameliorate
To ameliorate is to improve or make better. (verb)
An example of something that ameliorates is ibuprofen when used to help a headache.

Webster's New World College Dictionary
Ameliorate
transitive verb, intransitive verb ameliorated, ameliorating
to make or become better; improve

American Heritage Dictionary 4
Ameliorate (ə-mēlˈyə-rātˌ)
tr. & intr.v. a·me·lio·rat·ed, a·me·lio·rat·ing, a·me·lio·rates
To make or become better; improve. See Synonyms at improve.
Related Forms:
a·melˈio·ra·ble (-rə-bəl) adjective
a·melˈio·raˌtive adjective
a·melˈio·raˌtor noun
Not sure but I think those are curse words or some kind of Apple language?

DG

You don't know my mama, Denny. She is still kickin'(barely) and she'd be glad to correct you (as she still regularly corrects her four 60+ year-old sons - we say "yes Ma'am").

That's enough, class.