Insulation

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  #1  
Old 07-15-02, 04:20 AM
FROGG469
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Insulation

I HAVE JUST BUILT A GARAGE AN AM GOING TOO PUT TIN IN FOR THE CELING. SOMEONE TOLD ME IF I BLOW INSULATION IN ON TOP THE TIN IT WILL COLLECT MOISTURE AND CAUSE MY TIN TOO RUST OUT. IS THIS TRUE? IF SO HOW COULD I INSULATE IT AND NOT HAVE THIS PROBLEM? THANKS FOR YOUR TIME!!!
 
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Old 07-15-02, 04:33 AM
bungalow jeff
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You shouldn't have a problem since the tin would go on drywall, or greenboard if you are worried about moisture.
 
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Old 07-18-02, 12:12 AM
FROGG469
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Question

Thanks for the info.. But i am going too screw the tin straight too my rafters.. So in doing it this way will have too worry about the insulation causing any problems with my tin.. Thanks for your time.
 
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Old 07-20-02, 08:58 PM
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Rust on tin

When warm, humid air condenses on cooler surfaces, such as tin ceiling or other metal objects prone to rust, rust will be a problem. As temperative and humidity tend not to be controlled by HVAC systems in garages, rust is a potential problem for tin ceilings whether installed directly to rafters or over drywall. Oil-based paint may offer some protection.
 
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Old 07-21-02, 10:09 PM
FROGG469
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Plastic

I have some plastic left over from pouring my slab. Would it help much if I were too put this up befour I put the tin up? It's fairly thick 6ml I think. Thanks!!
 
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Old 07-22-02, 03:34 PM
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Insulation and vapor barriers

There is no thermal boundary between an unconditioned garage and its unconditioned attic. Insulation is installed to prevent heat from escaping from heated areas of your home such as exterior walls and ceilings that surround the heated spaces because heat escapes to the outdoors. In summer, the hot air enters our homes and we have to air condition to pull the hot, moist air outdoors.

"Thermal Boundaries are the parts of the home that physically separate the conditioned space of the home from the unconditioned spaces. This is where insulation should be applied and where you get the most efficient use of insulation. An example of this is a home with an attached garage. The wall that separates the living space and the garage is part of the thermal boundary, whereas the wall that separates the garage and outside the garage is not." Thermal Boundaries. Resercon Co. Retrieved 22 July 2002. http://www.resercon.com/Thermal.html

"Vapor barriers were invented for insulation. That means it is only used with insulation. When homes were not insulated, there was no need for a vapor barrier. Once insulation was put in a home, it was found out that a moisture problem occurred within the insulation. Since all heat has moisture in it and the dominant heat transfer mechanism in heating is diffusion, it was apparent the moisture problem was a result of dew point being reached inside the insulation. There are basically two ways to prohibit heat from condensing inside insulation. First is to reduce the volume of air inside the insulation, which was not feasible when insulation was first introduced because the thermal effect came from trapped air inside the insulation. The second is to reduce the amount of humidity in the heat so that when dew point is reached inside the insulation it could not condense. Vapor barriers do not address diffusion, what it does is prohibit the heat inside the insulation from condensing by reducing the moisture content in the heat. Vapor barriers are rated for performance just like insulation. It is recommended the rating for vapor barriers should be SP-15. This rating has nothing to do with rating the insulation. Though the vapor barrier may have some thermal effect, it will be rated in "R" values with the insulation, a separate and different performance rating.

Where and when should a vapor barrier be installed? This is where all the conflicting theories come from. In areas where you have cold winters, the vapor barrier should be between inside the home (heated areas) and insulation. In areas where the climate is dry, no vapor barrier. In areas where it is hot and humid, the vapor barrier should outside the insulation and the home. Where vapor barriers are applied the factor that you should be concerned about is heat is attracted to cold and heat condenses on cooler surfaces. In fact, surfaces inside the insulation qualify as a cooler surface. Where vapor barriers should not be applied, the factor you should be concerned with is equilibrium relative humidity. What this fancy term means is, if the air is very dry, it has the capacity to absorb the humidity in any heat present, thereby prohibiting condensation. It also means that if the heat is dry, it does not possess the ability to condense inside insulation. This is why in dry climates vapor barriers is not recommended.

In areas where you have cold winters, the heat inside he home is attracted to the cold outside. Since heat usually condenses against cooler surfaces and surfaces inside the insulation qualify as a cooler surface, the vapor barrier is put between the insulation and inside the home. This is done to prohibit condensation by reducing the moisture content in the heat.

In areas where it is hot and humid, the heat outside the home is attracted to the air conditioned space inside. So the cooler surfaces where the heat will condense is inward when cooling a home instead of outward when heating a home. Therefore the vapor barrier should be between the heat outside and the insulation. The problem with cooling is that the dominant heat transfer mechanism is radiant, unlike with heating, itís diffusion. To alleviate this problem, most contractors will use foil faced insulation, where the foil vapor barrier acts as a radiant barrier too.

I am aware that this raises more questions than answers. The sole purpose was to take away some of the confusion with insulation and understand the different applications with it. For those that require more information, you can e-mail me by clicking on ask an expert." Insulation. Resercon Co. Retrieved 22 July 2002. http://www.resercon.com/Insulation.html

The metal surfaces in a garage tend to be cooler than the warm, humid air found in the unconditioned space. Thus, condensation forms on the cooler surfaces, frequently resulting in rust. Thus, the explanation of rusty, insulated refrigerator doors frequently found in garages.
 
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Old 07-28-02, 08:37 PM
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I'm not sure why anyone would use tin instead of sheetrock?
 
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Old 07-29-02, 05:11 PM
rbisys
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Geetings,

If you install a 2 or 3 layer radiant barrier (RB) between the joist first you will not have to worry about condensation, also the RB will not be in contact with the ceil material. In fact, depending on the type material used for the ceiling panels they could be a fairly good RB themselves. This method will out perform any fiber material you could install. You will not have to worry about mold or carcenogenic fibers or chemicals either. Condensation can be a worse problem in garages with fiber materials than in the home because of the different temperature dynamics there.

I would suggest you install a 2 layer material in the walls too.

Thank you for considering my opinion.
 
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