Another Reflectix Question

[Jimroll]

I have read many of the threads about Reflectix, many of which appear to be old. My question is for those who have installed Refletix, do you find that the installation time pays off compared to simply using fiberglass bat? From what I have read cutting and installing spacers to create an air gap is time consuming. Did you install a single layer or two? Would you do it again?

Thanks
Jim

[HiJoeSilver]

I'd do it again. I did 2 layers with 1/2 space between outer skin and first layer and 1/2 between that and next layer.

Cutting spacers does take some time but you can do a lot at once. I used a 4'x8' sheet of 1/2" foam board. Cut 1"x48" strips then marked 1" from end of a wood board. Put a box under the end of the board put the foam strip down flush to the end of the board and sliced with an extendable razor knives at the 1" mark. Slid the strip forward, knocking the cut block off the edge and into the box. Repeat 4600 times, not necessarily all at once. Goes pretty quick though.

I used roofing polyurethane caulk to glue the blocks in place somewhat randomly in a bunch of bays and then let cure then went back and put the prodex in. I sandwiched wires between layers.

Either way only 1.5" doesn't help but the prodex does seem cooler.

[65CV]

Jim-

For our camping, I'd absolutely use 2 layers of prodex again. There was an older thread -- wish I could find it -- where a member cut 1' x 1' test panels and put thermocouples behind the panels. He found that prodex worked better in hot, sunny weather while fiberglass was more effective in the cold.

I've put my hand on the inside panels of both prodex and fiberglass insulated airstreams on the same day and found the prodex to be definitely cooler. Since we tend to be in warmer weather, our choice is reflective insulation.

We cut strips of prodex, glued them to the outer wall, glued one layer, more strips, then another layer. I found that to be easier than cutting foam strips as I did on an earlier restoration.

Note: prodex, not reflectix. It seems to be a sturdier product with more closed cell foam to encapsulate air and reduce heat transfer.

John

[perryg114]

I put two layers of R-MAX 1/2" foam and one layer of Refletix and that gives you more R-value than fiberglass.

Perry

[65CV]

Rigid closed-cell foams do have a good R-value. I've never used foam and would caution you to research them well. Some have reported here that rigid foams do degrade and turn to dust over time. There was speculation that this occurs with more miles over the road.

I'm not speaking from experience -- just pointing out what I read as I researched my insulation choice.

[HiJoeSilver]

"Note: prodex, not reflectix. It seems to be a sturdier product with more closed cell foam to encapsulate air and reduce heat transfer. "

Good point! I used mostly prodex had to finish up with a little reflectex. Definitely a difference. The prodex has more of a. continuous foam between shiny sides. The reflectex is more bubble wrap with shiny sides.

[perryg114]

I expect over time the aluminum layer corrodes off and you are left with very little insulation at that point. Also it will degrade from dirt and mold over the years. The R-MAX foam has aluminum on both sides to strengthen and contain the foam. It also acts as a radiation barrier as well. So you really have two products in one kinda like the prodex. Having two separate layers with 4 interfaces helps even more. If you want to add some of the bubble wrap over that, that helps even more. Also none of this stuff will stay soaked with water a long as you leave the bottom edges open.

Perry

[Jimroll]

Thanks for your thoughts everyone. Sounds like prodex or r-max is the way to go. I have used solid foam board (the pink stuff) in two other campers that I built and it seems to have worked well but that is labor intensive as it has to be kerfed around curves then channeled out for wires. I suppose that in time anything will will degrade as the fiberglass has.

[65CV]

For yet another opinion, listen to this week's episode of thevap.com