Best Three Season Bottom Floor Insulation

TECMike wrote:
Been trying to wrap my mind about how to go about insulating the bottom of our three season trailer. Our little Sunnybrook Harmony has exposed tanks and I am in the process of installing tank heaters. However I would like to add a little insulation to the bottom, which has a black composite material covering the bottom of the floor.

I have asked this question before, but am having a problem understanding how to choose a product that will not cause a problem with moisture to the existing floor structure.

Also I have eliminated spray foam as a choice as I can see it being a problem if I ever need to gain access to the underside flooring.

So is there a product that both breathes and provides insulation at the same time that might fit my application? Thanks in advance. Mike

Why not just enclose the underbelly area. Mine came with a single sheet of coroplast screwed into the edges of the frame rails. What I did because I was painting my frame is that I sectionalized the entire underbelly into 4' sections that can be individually removed for access to the underbelly area and while I was at it I added some of the board type insulation (R-5 rating) to about 65% of the area between the frame rails. The design I developed and used requires no holes to be drilled into the frame and could easily be added to a trailer w/o an existing enclosed underbelly for a reasonable cost ... in the neighborhood of $300 or so as a WAG with the biggest cost being the aluminum angle iron for the supports and the 1/4-20 nylon bolts, washers and nuts and of course I already had the coroplast material. THIS ALBUM shows the details with detailed descriptions in the captions to the various photos. That album has some additional info on my frame issues, gas line re routing, etc., but all the underbelly work is in there.

This mod would also allow you to add some sort of heating to that area if needed or desired.

NOTE: while I was able to use some of the existing holes to better secure the edges of my underbelly sections you could simple add sections of al. angle iron along the edges in place of where I put the sections of the acrylic "U" channel I made from some leftover wallpaper corner protector I had laying around.

Larry