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I been trying to figure out how to insulate the rib cavities in my cargo van. Some, like cotton or cellulose will absorb water, creating a problem with mold. Some, like foam, may not cure properly and rust the vehicle from the inside out, not to mention it can push your side panels outwards. Some like styrofoam beads, may become electrically static and not move to where you want them to.
How about stone wool? I know they come in batts, but it can be broken down into pieces small enough to fit into tiny rib sections.
Any wise word on stone wool?
Here's a pic:
[Image: ududumyp.jpg]
It should have much the same problems as pink fibreglass insulation and hold water, leading to mold/rust. They use rockwool cubes (basically the same thing) for hydroponics. ..Willy.
Stone wool will not absorb water or fester mold. For that reason I'm considering it as my top rib insulating method.
Glass fiber will not absorb water either (allow water into its cell structure). However, a rock fiber bat (or glass fiber bat, steel wool, nylon scrubby, etc.) will hold water in its matrix (between fibers). Water cannot penetrate closed cell foam like Formular (or reflectix), in which all the little air pockets are surrounded by a waterproof membrane.

This is not to say it won't work (double negative Blush ). It is just that your premise is not correct: water can be retained in the bat. IMO fiberglass bats would work just as well and be cheaper. Just have to make sure they stay dry! -- Spiff
(06-10-2014, 03:47 PM)Spaceman Spiff Wrote: [ -> ]Glass fiber will not absorb water either (allow water into its cell structure). However, a rock fiber bat (or glass fiber bat, steel wool, nylon scrubby, etc.) will hold water in its matrix (between fibers). Water cannot penetrate closed cell foam like Formular (or reflectix), in which all the little air pockets are surrounded by a waterproof membrane.

This is not to say it won't work (double negative Blush ). It is just that your premise is not correct: water can be retained in the bat. IMO fiberglass bats would work just as well and be cheaper. Just have to make sure they stay dry! -- Spiff

Spiff, I agree with you, even though water won't permeate through the material, water can still be caught in between the fibers and crevasses.
So what should be used in the ribs?
spiff is right even with a double negative. luis when you said spray foam did you mean the stuff that comes in aerosol can from home depot? I wouldn't use that. the spray on foam like they use for houses would be ok if you used closed cell, but it is very expensive. what about foam board. you do have to shape it to fit the curves but I think it's the best alternative. highdesertranger
(06-10-2014, 06:37 PM)highdesertranger Wrote: [ -> ]spiff is right even with a double negative. luis when you said spray foam did you mean the stuff that comes in aerosol can from home depot? I wouldn't use that. the spray on foam like they use for houses would be ok if you used closed cell, but it is very expensive. what about foam board. you do have to shape it to fit the curves but I think it's the best alternative. highdesertranger

Hi there highdesert!
The spray foam was Dow two part foam that cures in seconds. But I hear it can cause rust, lots of it!
If you look at my build, the ribs on my van don't allow foam board to be inserted, the holes are too small.
luis is that dow foam closed cell? if it is it shouldn't cause rust. call dow and ask about the rust issue. sorry I missed the pics. can you point me it the right direction to see them. so I can see why the foam board will not work. highdesertranger
Hey Louis, went back and reviewed your build thread to see what we are talking about. I see what your issue is with the ribs with small openings.

Here are your options as I see them right now:
1. Just leave them empty. You will loose some heat through them. Most of the heat lost through the ribs will be lost due to conduction anyway.
2. Stuff fiberglass into them and live with the possiblity of it getting wet. Somewhat hard get a good distribution unless you are anal about it. Will settle over time.
3. Fill it with styrofoam. Bean bag chair filler would work, but would get all over if you are not careful. And would be difficult to do on roof. Packing peanuts would also work, but would be putsy. Either will settle over time.
4. Find an injectable foam that is used in steel structures. Probably expensive and would require specialized equipment.
5. Wrap them. You will lose inside height and width.

A lot depends on the outside temps you are dealing with. With a low of 30°F, I wouldn't worry about it. 0°F or lower, I'd do the fiberglass thing (and probably wrap them also). It just depends on how much heat you can afford to loose.

Hope my rambling has sparked some ideas for you. Hopefully someone else will come up with an elegant solution for you. -- Spiff

P.S. Just saw Highdesertranger's last reply. I don't know anything about the home insulating foams. Only heard somewhere that one of the chemicals used is corrosive to metals. Good advice to talk to manufacturer about it.
(06-10-2014, 09:01 PM)highdesertranger Wrote: [ -> ]luis is that dow foam closed cell? if it is it shouldn't cause rust. call dow and ask about the rust issue. sorry I missed the pics. can you point me it the right direction to see them. so I can see why the foam board will not work. highdesertranger

Sure; 2014 Chevy Express 2500 van build: luisafernandes

(06-10-2014, 10:07 PM)Spaceman Spiff Wrote: [ -> ]Hey Louis, went back and reviewed your build thread to see what we are talking about. I see what your issue is with the ribs with small openings.

Here are your options as I see them right now:
1. Just leave them empty. You will loose some heat through them. Most of the heat lost through the ribs will be lost due to conduction anyway.
2. Stuff fiberglass into them and live with the possiblity of it getting wet. Somewhat hard get a good distribution unless you are anal about it. Will settle over time.
3. Fill it with styrofoam. Bean bag chair filler would work, but would get all over if you are not careful. And would be difficult to do on roof. Packing peanuts would also work, but would be putsy. Either will settle over time.
4. Find an injectable foam that is used in steel structures. Probably expensive and would require specialized equipment.
5. Wrap them. You will lose inside height and width.

A lot depends on the outside temps you are dealing with. With a low of 30°F, I wouldn't worry about it. 0°F or lower, I'd do the fiberglass thing (and probably wrap them also). It just depends on how much heat you can afford to loose.

Hope my rambling has sparked some ideas for you. Hopefully someone else will come up with an elegant solution for you. -- Spiff

P.S. Just saw Highdesertranger's last reply. I don't know anything about the home insulating foams. Only heard somewhere that one of the chemicals used is corrosive to metals. Good advice to talk to manufacturer about it.

Spiff, great ideas good points. I'm going to google steel safe foam, maybe I'll come up with something.
Thanks.
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