does anyone have any suggestions on what type of insulation to use before i put my wall boards on my friend used duct board and when  her trailer would  sweat it caused the duct board to soak up the water and in turn swelled the wall boards it is a mess so i thought of styrofoam or spray foam which is very expensive so any suggestions will be a big help

thanks for reading

I used foil backed bubble wrap on mine. This stuff is easy to work with and you can get it in a wide range of R ratings.Heres a link to some

http://www.insulation4less.com/Insulation4lessProduct-14-Reflective-Bubble-Reflective-4-ft-x-125-ft-500-sq-ft.aspx

Just use the foil tape that HVAC people use on the duct work on houses and seal off EVERYTHING. You wont have any problem with it sweating and warping any boards

Here is a link to my trailer upgrade work

http://pets.webshots.com/album/573068102VpSZxX

Have fun on your trailer upgrade

I am just doing the living quarters in my trailer. I have a Kiefer and there is 1" depth between the supports, I used pink 1" foam board and was wandering if I needed to use the foil tape around each little section? Would that help with the condensation?

I am in the process of finishing the interior of my dressing room in my new 4-star gooseneck.  Did the ceiling first.  The ceiling studs have 1" depth and I used 3/4" rigid (pink) foam board insulation.  (Tried to use 1", but somehow that ended up exceeding the depth of the stud and would not allow the wall board lay flush against the roof studs, so we went to 3/4" instead.) 

I cut each section of rigid insulation just a hair larger than the measurement of the opening, so as I installed it, the insulation board really wedged tightly between each stud and the sides.  I did not tape anything (only out of ignorance -- didn't know I should).  Didn't have to worry about the insulation falling out before I installed the wallboard, once it was in, it was in for good!!  I then applied 1/8" wallboard over that and screwed to the studs (the wallboard has a shiny white finish on one side -- makes you think of a dry erase board).  Total cost for the insulation, wallboard, screws and all the trim pieces totalled right at $200.  I had an estimate from a trailer repair shop, they wanted $700 for the job.  There are a few minor places that cosmetically don't look great (mostly in the trim) but I can overlook that for a $500 savings. 

I camped in the dressing room over the weekend, down to 25 degrees outside.  Ran my propane heater to stay warm and watched for any sign of condensation on the ceiling.  I did find one very fine line of condensation at the edge of one of the studs, but the rest of the ceiling was condensation free.  My guess is that somewhere along that stud there is a gap in the insulation which is allowing cool air to pass along that stud and causing the condensation to form.  It was such a very fine line, I don't think at this point I need to un-install that portion of the ceiling to tape and reinstall the wallboard.  But I will keep my eye on that area for a while to be sure it does not cause damage to the wallboard.

All the interior walls were covered in condensation by the AM, so I'm tackling those next.  Bought the insulation today and hope to have the wallboards installed on Saturday.  Another $200 project but in the end I'll have a finished dressing room, and at a fraction of the price of having it done by a professional.

I will venture that most of the condensation and moisture that sweats, Comes from inside the trailer.  Each breath that a person take exhales moisture. The steam from cooking, hot water in the sinks and shower, all contributes to the interior humidity of the trailer.

I used to have a building inspector that required a vapor barrier on the inside  of all wall cavities. We had to bring in insulation experts and show him that more moisture penetrates into the wall cavities through a single gang electrical wall outlet than through an entire sheet of sheet rock. If you are concerned about moisture getting into your wall cavities, Your efforts are much better spent sealing up any penetrations of the interior and exterior wall surfaces.

Condensation or sweating occurs when you have a differential of temperatures. The example of glass of a cold drink sweating on a hot humid day. Insulation helps prevent the sweating by stopping the difference of temps on the inside and outside of your wall skins from touching each other.Thats why you don't want a single walled trailer. You want some insulation sandwiched in between the two surfaces. Temperatures change faster if air can move. Thats why most insulation attempts to stop any air movement with in the cavities, Taping joints is just method to slow air movement around your insulation.

Heat/Cold move via three modes. Convection, Conduction and Thermal radiation. A Foil face stops the thermal radiation by reflecting it. This is how a thin mylar space blanket keeps you warm by reflecting your own body heat back. Trapped air in low density foam or bubble wrap or other forms of insulation stop the conduction. By making it difficult for the heat to move through the material. Filling the void completely and stopping any air movement stops the convextion of air moving with in the cavity.