Insulation

[Dave rem]

Have read quite a bit and looking for opinions. AS gutted. Everything sealed including windows. Time for insulation. Glass batting would be the easiest but looking for the "best".Saw where little pieces of foam where cut and then sheets of reflectix were installed. Process was repeated. How does solid foam such as Dow Styrofoam work with a sheet of reflection after? Will go with whatever forum thinks is best. Want to do it only once! Thank you for your insights and ideas!

[Unka Jack]

Just in the middle of insulating myself. I'm using the Styrofoam and Prodex method myself. If you check my thread, you can see the progress. ( http://www.airforums.com/forums/f44/...-113780-5.html )

Lessons learned:
1) From my pics you can see just how effective just 1 layer of Prodex is, however, aluminum is an excellent conductor of heat. notice the melt spots near the ribs on the roof. I'm planning on using some sort of thermal break between the ribs and inner skins.
2) Putting the 1st layer is a fiddly job but the second goes on much faster.
3) If I had to do it all over again, I'd probably use Roxull mineral fiber batts instead. mostly for the slightly less cost and ease of installation.

FYI, Roxull has a commercial product called "Firebatt" that is the same material, but comes in smaller thicknesses that wouldn't require splitting the batt to fit in the wall space.

Good luck or your project, post lots of pics.

[Belegedhel]

My recommendation: Don't over-engineer it. You have 1.5" to work with. You can stuff it with rock wool, fiberglass, shiny bubblewrap, foam-board, spray foam, micro-spheres, sawdust, or any combination of the above. End of the day, you will get about R6 or R7. If anyone claims better than that, they are being really creative with the truth.

The different materials have their own pros and cons, but you have to decide what is "best" for you. For cost, and ease, you probably can't beat fiberglass, but critters makes homes in it, and popular belief is that it traps water. Rock wool is less water trapping, but still a good nest for critters, and it is harder to source. All reflective bubble-wraps require air-gaps to achieve thier professed R values. Do the math before believing you will achieve R16 with a piece of reflective foil.

Myself, I overengineered it, used a layer of solid foam paired with another layer of soild foam with a reflective outside for the bottom ~24" of the walls (these added up to 1.5"). Above that was fiberglass with a reflective layer (this stuff is sold to be used as duct insulation--good news is that it is 1.5" thick, so no splitting is required). My rationale was that I wanted solid stuff at the bottom of the wall so critters didn't nest in it, and if a puddle forms there, that there is no "wicking" action.

At the end of the day, your weakest points, insulation wise, will be your windows, which will bleed heat no matter what you cram into the walls.

Good luck!

[Mixter]

Originally Posted by Belegedhel

Myself, I overengineered it, used a layer of solid foam paired with another layer of soild foam with a reflective outside for the bottom ~24" of the walls (these added up to 1.5"). Above that was fiberglass with a reflective layer (this stuff is sold to be used as duct insulation--good news is that it is 1.5" thick, so no splitting is required). My rationale was that I wanted solid stuff at the bottom of the wall so critters didn't nest in it, and if a puddle forms there, that there is no "wicking" action.

Good luck!

Hey Belegedhel- do you have any pics, tips and tricks for your method? I kind of like that idea. I was just going to keep it easy and go back in with fiberglass... From everything I've read, I think the insulation r value level will be as good it gets- or close enough. Its the water thing that I dont like about it. Inevitably, there will be a leak. I just want it to dry fast when it does.

[Belegedhel]

Well, since you asked, I dredged up this picture. Upon inspection, I am reminded that I used the solid foam stuff basically from the floor to the bottoms of the windows, where the wall really starts to curve more, then switched to the fiberglass with shiny side above that. This picture has some inside skins (shiny without markings), some exposed solid foam board with the shiny side in (says "permatex" on it in blue), and some exposed fiberglass with the shiny side in. The pink stuff you see looking into the front end-cap was just plain pink fiberglass with a layer of reflectix on the outside, toward the shell.

As to philosophy about whether to have the reflective stuff closer to the inner skin or outer skin, I looked at it two ways:
1) If I think of the blistering outside (in the summer) as being the inside of a heater duct, then the "correct" installation of the duct wrap would be shiny side toward the cool area (the inside of the trailer). How's that for inside-out logic?

2) All of the reflective radiant barriers require an air gap in order to be effective. I figured that the interior wall space, occupied by the fiberglass would be a little bit of air gap, and I would gamble that the shiny stuff is shiny on both sides, so it would function to reflect the Texas sun back outward. Had I turned it the other way, then it would reflect my interior heat back at me, but there would be no air gap on the heat-of-the-summer-sun exterior skin side.

Good luck!