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Mon Aug 13, 2012 8:42 am

A guy I chatted with at the gas station told me he had insulated his Bay by stuffing regular fiberglass insulation into plastic bags and heat sealing them, and stuffing that into the interior panels -- obviously to prevent the moisture absorption of not using the plastic.

Is that legit? Has anyone else done this? Is it that simple or does this cut down the R value ... ?

Mon Aug 13, 2012 10:00 am

It's a great idea. Owens-Corning even recognised that moisture absorption was a problem with fiberglass wall batts and started selling loose batts encased in a sealed VB, they did that years ago.

Mon Aug 13, 2012 10:41 am

Awesome. R32 here I come.

Mon Aug 13, 2012 10:58 am

What will diminish the R-value of dry batt insulation is packing it more tightly than it's design thickness. A 6" batt stuffed into a 4" stud bay will not deliver a higher R-value than the 4" batt installed correctly, it can even be worse. An 8" batt into a 4" bay is definitely worse. So don't overstuff, you'll be working against yourself.

And obviously your VB has to be completely sealed, or else it will admit moisture but severely delay or even prevent the batts drying.

Mon Aug 13, 2012 11:01 am

Compressing more fiberglass into a tighter space does not increase the insulation value. The fiberglass itself is fairly low in insulation value. The insulation value is measured by the thickness of the fiberglass when expanded and with how much air it traps. Compressing it to be more dense does not help because it reduces the amount of trapped air. Buy the thinnest batt you can find to fit in a 1-1/2" space. R-32 comperessed down to 2" is more like R-8.

Mon Aug 13, 2012 11:11 am

My interior panels are wood now and quite a bit more than the original width because they're not curved in. Explanation will be useful to others though.

Any opinions on the reflective stuff?

Mon Aug 13, 2012 11:16 am

the bags won't conform to the shape of the cavities, and moist air will get around them and you will get condensation on the body panels. That is the moisture that causes seem rust, from the inside out.

A thin layer of spray-on material that covers panels and seals joints etc preventing moist inside air from contacting cold outside panels is what you need. Make sure the van is very dry inside before you apply it.

I was recently inside a heavy steel shipping container that had been treated that way and the effect was quite obvious.

Mon Aug 13, 2012 11:26 am

240Gordy wrote: A thin layer of spray-on material that covers panels and seals joints etc preventing moist inside air from contacting cold outside panels is what you need.

Like what? Primer?

Mon Aug 13, 2012 11:52 am

...or bedliner?

Mon Aug 13, 2012 12:04 pm

Very cool, very timely. Fridge is out, may re-use stock insulation if in good shape. (and hopefully not too many signs of rust! "crosses fingers") Thanks for posting that idea.

240Gordy makes a good point. Adding to that, if there's issues with seals or whatever, moisture will get in to that area. I guess all we can do is slow the process down.

Neil.

Mon Aug 13, 2012 12:48 pm

maybe Waxoyl http://www.waxoyl-usa.com/products/corrosion-prevention

Mon Aug 13, 2012 1:02 pm

The foil/bubble/bubble/foil insulation for water heaters, etc has an R value from R6.7 to R11, depending on the size and brand. I think its perfect for Westy use: it is very light, it rejects radiant heat and it doesn't hold moisture. Glue it to the body panels with polyurethane caulk and it deadens the panels too. What's not to like? ;)

http://www.ecofitt.ca/Products/Weatherization_Prod...on-Blanket

Mon Aug 13, 2012 1:26 pm

Jake de Villiers wrote: Glue it to the body panels with polyurethane caulk and it deadens the panels too. What's not to like? ;)

Caulk it and faulk it. Right on.

re: bedliner/waxoyl -- great ideas.

Mon Aug 13, 2012 1:44 pm

Jake de Villiers wrote: ... What's not to like? ;)

The lack of an ASTM spec.

Mon Aug 13, 2012 3:36 pm

randywebb wrote: Jake de Villiers wrote: ... What's not to like? ;)

The lack of an ASTM spec.

Boo-hoo!

Mon Aug 13, 2012 4:12 pm

Jake de Villiers wrote: randywebb wrote: Jake de Villiers wrote: ... What's not to like? ;)

The lack of an ASTM spec.

Boo-hoo!

I'm also a little skeptical of some of the claims for insulation effectiveness for the products including radiant barriers. They talk about the efficiency of blocking radiant heat, but that's not a big problem compared to conduction and convection inside a wall. If you're using it to insulate your windows, sure. But inside the van? I'm not convinced.

Mon Aug 13, 2012 5:22 pm

I'm not convinced either. And I used to give people PhD's in heat transfer in animals.

Everyone should beware of hyped ad claims.

Mon Aug 13, 2012 6:23 pm

randywebb wrote: I'm not convinced either. And I used to give people PhD's in heat transfer in animals.

Everyone should beware of hyped ad claims.

Certain presidential races come to mind.

If the inner panel is sealed up enough (paint, liner, wax, whatever), and the bagged insulation is properly filled, will the condensation really be a factor on those panels?

Fascinated.

LP

Mon Aug 13, 2012 7:11 pm

chojinchef wrote: randywebb wrote: I'm not convinced either. And I used to give people PhD's in heat transfer in animals.

Everyone should beware of hyped ad claims.

Certain presidential races come to mind.

If the inner panel is sealed up enough (paint, liner, wax, whatever), and the bagged insulation is properly filled, will the condensation really be a factor on those panels?

Fascinated.

LP

no bag is going to conform to the shape of the cavity.

the whole mess will sag and moist air will get behind it and you will get condensation on the cold panels. That is what destroys the bottom of the panel behind the westy kitchen.

seriously, google condo rot, same thing will happen to your van, either you heat that space or you seal it off with a robust vapour barrier.

by spray on material I mean some expanding foam that will not absord water, a do not spray so much that it fills the space, just maybe an inch thick or so, and don't fill up any nooks such that the foam will expand and deform the panel.

Mon Aug 13, 2012 7:28 pm

240Gordy wrote:
no bag is going to conform to the shape of the cavity. Come on, it can be convinced, there's no time for pessimism...

Interesting.. this guy swears by the silver foam core stuff, and as our old friend Foghorn Leghorn says, "you can't argue with figures son, cause figures don't lie"

http://www.shanescitshed.com/cx2500/air-con/citroen_cx_insulation.html[/url]