The great insulation debate revisited!

[Minno]

Chris was too chicken (BKAAAAK - you knew the job was dangerous when you took it, Fred!) to post this question, but I like to live dangerously. For those of you that have reinsulated your trailers: we're looking at the differences between Prodex and fiberglass insulation, and whether it's worth the extra expense to do Prodex. Keep in mind that we live in Minnesota, are planning on winter traveling when we retire in the south. We've investigated the costs of Prodex and fiberglass, and the time involved in putting in Prodex, the R value of each, and we're still debating. I'm of the opinion that we should go with fiberglass, and Chris is still going back and forth. We had some major mouse infestations in Little Girl when we picked her up, but she had been neglected for many years, and we're not planning on letting that happen again. We've read and read and read the threads on insulation. Help!

Kay

[nmbosa]

I went though this debate a couple months ago and through a combination of laziness, running out of time, budget, and uncertainty over the benefits of Prodex, I ended up using fiberglass. However, I don't plan on doing much winter camping and even summer camping up here in the Northwest is fairly mild in terms of heat. So I was not really trying to get a house like R-value out of my insulation.

Done correctly, it seems like the Prodex can give excellent R-value, but doing it correctly involves a significant time investment (in addition to the cost) and very particular attention to detail.

[Minno]

The only other to add I that when we gutted her, there was only one place where the wall/ceiling insulation was wet or had been wet (i.e., black & gunky). One shell leak around one window after 37 years. So, we're not too concerned about future water leaks ruining the fiberglass insulation either.

Norm & Mary - Kay feels vindicated.

Chris

[purman]

Has anyone ever thought of using a spay in foam. it sure would do a nice job of sealing everything. We used it on the last house I built. It was a high dense foam the expanded only a little so there wasn't much trimming to be done. and on a 2x6 wall we got about an R26 out of it.

[Minno]

My understanding from experienced people is that it would fall apart from the vibrations and flexing when you tow. Experts say it powders out after a short time.

Kay

[Canlib]

I just finished removing the interior skin from my 68 GT and having seen the mouse infestation, water damage and settling of the old fiberglass, I would sooner not use insulation than repeat the fiberglass. I have used professionally applied spray foam in a number of home renovations, but I can't imagine the time it would take to detail the foam so that the inner skin could be reapplied. (those pesky curved surfaces) Soooo, I think I'll use Prodex (or an equivalent material from a Canadian supplier to avoid cross border shipping).

Ian

[GR8DANE]

I have heard 2 things about the reflective bubble insulation that I like a lot. Uwe says "mice don't like it." Many say that it keeps the trailer substantially cooler in hot weather. Use both the reflective and the fiberglass and get the desired results.

[Jim & Susan]

I used reflective bubble with about a 1" layer of pink stuff over that. I can say unequivocally that I would NOT do that again. Have a look at my Full Monte thread if your interested. The foil stuff is a pain to work with, costs too much and I may have installed wrong (sealed it up too tight).

Zepelinium has a thread here someplace showing results of testing he did on various types of insulation. The pink stuff held up very well vs. the others.

Just my 2 kopecks. YMMV.

Jim

[MDSilverado]

I have been contemplating the same topic for some time and finally settled with 2" polystyrene board on the underbelly and fiberglass in the walls. I saw very little if any signs of mice infestation and expect that if it does happen it will more than likely be in the underbelly than walls. So I will not use fiberglass in the underbelly. I sealed the edges of the polystyrene with spray foam or caulk depending how tight the gap was at the edges. The 2" polystyrene was $39.00 and I think I will end up using four sheets total. I tried working some with the Prodex and found that it was very difficult to seal the edges. And as with all insulation if there is any violation of the barrier (gaps at the edges) then the heat/cold will transfer around the insulation rather than through (much faster). The great thing about fiberglass is that you can cut it a little big and stuff it in and it will expand to fill the voids. Just dont cut it so big that you are compressing it substantially, that will reduce its R-value. Prodex due to its rigidity does not flex and expand like fiberglass and thus does not seal as well at the edges.

The other item I will be experimenting with is installing a thin piece of foam tape to the rip before installing the inner skin. This will hopefully prevent(slow) heat transfer from the ribs to the interior skin. I would think that due to the aluminum construction the skins and ribs are conducting a great deal of heat directly through the metal. Just my two cents...

[Minno]

Thank you for the responses. Part of our great hesitation in going with Prodex is the tremendous amount of time we think it would take to install it, especially in a 31 footer. We had pondered using Reflectix with fiberglass, but based on Jim's response, that doesn't sound like fun either! We think at this point that we will go with fiberglass and be vigilant about mice!

(Did anyone get the reference to "you knew the job was dangerous when you took it, Fred" ? Just curious if anyone else knew it.....)

Kay

[bgordon]

I've been reading over insulation tips/techniques quite a bit as I just picked up a gutted '48 14' Boles Aero. I'm leaning toward a foil/bubble insulation on the premise of air quality.

There is a similar product I just became aware of called TekFoil.
TekFoil, Reflective Insulation, TekFoil Reflective Insulation, Insulation Products, Energy Efficient Insulation - TekSupply
It is a reflective foil/bubble layer/reflective foil layering. There is also a double bubble version and a single ply reflective foil version if you want to layer over the pink stuff. The pricing seems comparable to ProDex.

Is there an aversion to the bubble layer? From what I've read ProDex has closed cell foam as the middle layer. It seems like there isn't an issue of the bubble layer bursting as one application is to use it under concrete floors. Any thoughts on TekFoil?
-Blake

[Dave Park]

I'm a bit confused with your reasoning on a statement you made.

You said, paraphrasing, "we're not concerned about water damage, because after 37-odd years, there was just one patch of water-damaged insulation."

A trailer going from 0-37 years will have a certain number of leaks. A trailer going from 38-74 years can be expected to have a lot more leaks.

Secondly, when refurbishing my last trailer, I invested several hundred dollars and about 50 hours of labor to reduce the weight by 100 lbs. In retrospect, I could have achieved the same weight loss for less investment and far less time by using the radiant barrier insulation.

Thirdly, nobody's mentioned in fiberglass' favor, it is a better sound insulator. I can't say how much difference this makes after two aluminum skins... but a good night's sleep is important to me.

My "forever airstream" will have radiant barrier insulation, because of the almost doubled R-value, the weight reduction, the pest-resistance, the water-resistance and because updating wiring later on will be a much less unpleasant task as needs change...

[Dave Park]

Originally Posted by bgordon

It seems like there isn't an issue of the bubble layer bursting as one application is to use it under concrete floors. Any thoughts on TekFoil?
-Blake

That is not a radiant barrier application of the product. Also, it's in static compression. The stress on bubbles in an airstream application is the easily 200F temperatures the outside wall can reach - the bubbles go through expansion cycles and are in tension. Over the years, they will leak.

That said, the primary action of the sheet is as a radiant barrier, and the bubbles play little part in that role. They are merely a low cost filler material to reduce conduction from one side of the sheet to the other, to reduce convection effects from sheet to air.

[SilverHoot]

I've done my bellypan area on my back in the dirt working with Prodex and will be doing the walls in a few weeks. I'm sure that the Prodex is more work than fiberglass, but is really not THAT difficult or time consuming. I found it pretty easy to cut to size with scissors and install.

[Dave Park]

Prodex - fit spacers, cut, tape into place.
fiberglass - dress well, cut, fit into place, shower, itch for a week anyway.

[gonorthwest]

I'm in the process of insulating the floor of my 1979 Argosy right now. I dropped the bannana wraps and belly pan. I'm not sorry that I did. The insulation was in such bad shape due to water intrusion it was essentially not there.

I decided to insulate with a rigid commercial grade polyisocyanurate insulation underneath the flat areas of the floor (R-18) and with a high density (R-15) fibergalss insulation in the bannana wraps. The poly iso was done in two layers layed in opposing directions and was tightly fit between the frame members and then run the opposite direction. The fiberglass was cut to fit and then slipped into the cavity between the sheetmetal and the bottom of the floor.

I applied a rubberized undercoating to the entire underside of the floor. I closed off the penetrations that were open with expansive foam, and I caulked all of the connections between the frame and the subfloor to control the movement of air from one area to another and to keep out bugs etc...

I also worked extensively to keep the water and out of the subfloor in the future. As a builder it makes absolutely no sense to talk about insulating a climate controlled space with the supporting floor full of moisture, the insulation full of water, and openings that permit the out door air into the area beneath the floor.

Hope this helps the debate. Please don't bomb me with info regarding combustability of poly iso. If you can fit into the belly pan to have a smoke, it's probably time to quit anyway!

[bgordon]

I had a quick question that I figured I would tack on here. I've read from numerous sources that it's a good idea to put foam/felt/something insulating strip between the ribs and the interior walls.

I'm working on a '48 Boles Aero and will have wood interior panels. Is that necessary in this application? Thanks.
-Blake

[DanielB]

Could you be talking about a vapor barrier by chance?
That is exactly a good place to put a vapor barrier I gather
Vapor Barrier – What Is It and How It Works | Home Insulation | Home Insulation Info

[Wabbiteer]

Nawsir, he's talking about hearing people wanting a thermal break to keep the aluminum interior panels-to-ribs from conducting heat madly as they do.

If I were attaching wood to the ribs I think I'd be exploring a tough painted coating over the rib contact area to keep the heat cycle heave & shrink and vibration from producing black aluminum oxide dust - one, its unsightly if it infiltrates the interior and two, it would be a squeak maker deluxe if there is any relative movement between the surfaces. Think Duck hunting call.

[DanielB]

Ceramic thermal coatings. A spin off from NASA.
All About Ceramic Insulation
Powder of ceramic air balls that you mix with paint.
Awesome.