Vapor barrier or not?

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Hacsta
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2017/03/04 09:19:41 (permalink)

Vapor barrier or not?

Hi Everybody, I searched for a answer but couldn't find one. I'm getting ready to insulate the walls of my food truck with mineral wool Roxul brand. I was wondering if I should put a vapor barrier up on the aluminum walls before insulating. Thanks for any help
#1

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    Hacsta
    Junior Burger
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    Re: Vapor barrier or not? 2017/03/04 10:13:48 (permalink)
    #2
    kreativekvs209
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    Re: Vapor barrier or not? 2017/03/08 01:04:41 (permalink)
    i don't think it would be necessary, because the aluminum does not rot. or rust like the metal ones do.
    #3
    Blakkmoon
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    Re: Vapor barrier or not? 2017/03/08 10:12:44 (permalink)
    I too am struggling with this issue.
     
    Please note: These are just my 2 cents - I don't have any REAL knowledge...
     
    - you can not stop condensation
    - if you trap it between between the aluminum and a sheet of plastic...
      gravity will take over and it run down the walls and pool on the floor
      where it will meet with your ( plywood ?? ) floor  -( rot - mold - yuk )
     
    I live in a cold climate and for many years, in the winter, I would put plastic on my windows, because it was supposed to "stop drafts" and "$ave energy" which is "good for the planet"
    The end result was moisture damage to the window panes, eventual rot and mold and the eventual need to replace the windows.   Now with PVC windows, there is no rot, just mold, and pooled water which eventually finds its way out and destroys the drywall.
    Now I leave the windows alone, and make sure that during the winter, my furnace fan is always running.
    No more moisture problems
     
    - if you put plastic between the insulation and the inner wall
      at least the insulation will help to disperse the water as it does not really absorb ( in theory )
     
    Insulation is designed to do this - let it pass through without absorbing like a sponge and allow moisture to disperse.
     
    - if you use NO plastic - the condensation could pass through the insulation and absorb into the ( plywood?? ) walls
     
    - assuming plywood walls - maybe coat/seal the wood ( paint? ) to block the absorption of water into the walls
    This may be the best option
    Its not like the walls are hermetically sealed.
    Hopefully the constant airflow of your fan will help to keep everything dry in and out.
     
    Maybe allowing some airflow and a fan to circulate air overnight when the truck is parked would be a good option as well.  That is the time you will get condensation build up.
     
    Often I have to wash some throw rugs.  If I let them hang dry in the shower, they can take 2 or 3 days before they are dry.
    If I make sure and turn on the bathroom exhaust fan, that cuts the drying time in half.
    If I toss a fan in there, it's dry in a few hours.
     
    I must be getting old, I can't just give an answer without a dang story to back it up !!
     
     
     
    #4
    kreativekvs209
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    Re: Vapor barrier or not? 2017/03/09 16:04:36 (permalink)
    Hacsta


    i think i've seen your video on welding up the horizontal beems through out the wall on youtube. was that you?
    #5
    sm1
    Junior Burger
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    Re: Vapor barrier or not? 2017/03/11 00:46:00 (permalink)
    I don't get why folks keep using wood on food trucks. Both of our trucks are aluminum and stainless. If we cover up the electrical, we can totally hose this them out. We usually do a couple of times a year.
    #6
    Hacsta
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    Re: Vapor barrier or not? 2017/03/12 18:24:41 (permalink)
    kreativekvs209
    i don't think it would be necessary, because the aluminum does not rot. or rust like the metal ones do.


    i'm starting to think the same thing . I'm not gonna use plywood and the mineral wood insulation doesn't absorb water. So i should be in the clear .  
    post edited by Hacsta - 2017/03/14 15:12:54
    #7
    Hacsta
    Junior Burger
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    Re: Vapor barrier or not? 2017/03/12 18:26:33 (permalink)
    kreativekvs209
    Hacsta


    i think i've seen your video on welding up the horizontal beems through out the wall on youtube. was that you?


    I posted the video to instagram .
    #8
    Blakkmoon
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    Re: Vapor barrier or not? 2017/03/15 23:58:29 (permalink)
    Not like I KNOW ...
    My understanding of the plywood was .
    1 - To help stiffen up the truck  .... Although I don't see this helping much.
    2 - More for securing items / equipment to the wall.
       - depending on the equipment - you can't always drive a screw into the metal beam ( unless you know where EVERY screw will go ahead of time )
    3 - A lot of people use FRP. It has to attach to something.
         Where I am FRP is used a lot!
         At $50 a sheet compared to $500 a sheet for stainless....  I see why.
    edit:
    One more reason I just thought about was ....
    Even IF you are lining with aluminum or stainless...  BOTH dent pretty easy ...  heck aluminum will tear..
     
    MY truck has 2 ft on center beams.
    If you were to push too hard on the wall ( cleaning ) between beams, you would eventually leave a wavy wall.
    Even if YOU are always careful.
    Employees won't be.
    Something could fall.
    Equipment could shift.
     
    So a backer board would help to prevent some damage.
    post edited by Blakkmoon - 2017/03/16 09:06:26
    #9
    kreativekvs209
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    Re: Vapor barrier or not? 2017/03/16 00:16:45 (permalink)
    I too am using plyboard on a wooden frame. because the frp have to be glued to something.
    #10
    acain
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    Re: Vapor barrier or not? 2017/03/16 09:15:33 (permalink)
    Here's an opinion, for what it's worth, and I certainly could be wrong, but it's my line of thinking.. I do alot of remodeling and construction. My understanding of why condensation happens to begin with is that the air on one side of the window/wall/pannel/whatever is cooler than the air on the other side. the aluminum pannel, lets say, might have a surface temp of, say sixty degrees if its cool outside, while it might be eighty in the kitchen. (or vice versa, mabey the sun warms the exterior while your a.c. keeps the kitchen cooler) at any rate, with NO insulation, condensation will form rapidly and abundantly. the better your r value, the less this will happen. The insulation here is doing two jobs. First, its keeping the kitchen (or house ect.) at a comfortable temp. But also, it's keeping the interior kitchen air temature from reaching the aluminum pannel. So... although it may be forty degrees OUTSIDE and seventy INSIDE.... as long as your insulation is doing its job, (keeping the inside air temp away from the pannel) the condensation simply wont form to begin with. Keep in mind, a vapor barrior doesnt STOP condensation from forming, it just keeps it from soaking through something. If it forms in the wall, its gotta go somewhere.  All that being said, and I apologize for the long ass post, vapor barrior always goes to the inside of the room. Perhaps considder the color of the exterior, lighter reflects heat away. Mabey vent the walls at the bottom, underneath. Use high grade insulation, mabey even spray foam. the better the insulation job the less condensation to begin with. And last, although this ones a stretch... try to keep the kitchen temp as close to the outside as possible. (of course thats not feasable in freezing weather :) )  Any way, good luck, and thats just what my brain was thinking, so mabey theres an idea in there some where that might be helpfull.
    #11
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