[MtDave]

This is probably a crazy idea otherwise I expect that one of you folks would have already thought of it and let the rest of us know. At any rate I was at Joann Fabrics with the wife this afternoon and walked by the quilt batting and foam area.

I find that they have a 100% polyester "Extra Loft" batting. That made me wonder if that would not be close to or as good as using Thinsulate in the roof ribs and other tight spots. Both are made with polyester although Thinsulate also contains polypropylene which is a very fine fiber.

The tag said that the batting is 1" thick and is punch needled. My wife says this is to keep the fibers together. It is dense enough that I was able to hold my hand behind one layer and not see any movement when I moved my hand. Comes on a big roll 45" wide and is $9.99/yard. Good thing is you can frequently get it for 40% off. Ok, with all that enthusiasm I'm ready to hear from those who are more knowledgeable about why this may or may not be a reasonable idea.

 

[seapro]

I think it would be great. For thermal insulation (not radiation from the sun) insulation is really just trapped air. Almost anything can do the job. I used the cheap pink stuff sold by the home improvement stores and have had no problems. If you are afraid of moisture you can install a low cost vapor barrier on the inside using the foil faced bubble or foam stuff about 1/4 inch thick available in rolls. the foil also does a good job of blocking radiant heat from sun light.

 

[medicineman4040]

We didn't use the cheap pink stuff, primarily used Thinsulate, but I fail to understand how 'glass' attracts or holds moisture. That's just not a physical property of glass...now denim seems to be extremely hydrophyllic.

 

[MsNomer]

i seriously doubt the Jo-Ann stuff will be satisfactory. If you could compare this side-by-side to Thinsulate you would see that the Thinsulate is much firmer, has more body, and has the scrim. Jo-Ann batting is intended to be sewn/tacked/encased in fabric.

Jo-Ann stuff also has a much lower R-value, like maybe R-1-2 versus R-5+. It is designed more for its fluff property than its insulating property. IIRC, Thinsulate has hollow fibers to enhance its R-value. I have made several backpacking quilts, for which R-Value is critical. There are special batts with R-values approximating that of Thinsulate--Climashield and Primaloft are the top ones. They cost as much as Thinsulate.

If you somehow managed to glue it to a surface, which would be difficult without scrim, I predict that in a short while the mass will sag leaving only the few strands that have adhesive on them. It might work for filling cavities, but if you use Thinsulate, you will have scraps for that.

Bottom line is that Thinsulate is designed specifically for application on vehicular surfaces. Save the Jo-Ann stuff for baby quilts.

 

[GaryBIS]

Hi,
One thing I would not do is put vapor barrier inside of the insulation. If you do this, you have a vapor barrier to the outside (the van sheetmetal), and a vapor barrier to the inside. Any moisture that gets trapped between the two vapor barriers has no way to dry out. In housing construction having vapor barriers to the inside and outside is a serious no-no -- I don't see why the same would not be true for vans.

My 2 cents would be that polyiso is a better choice in that its vapor impermeable -- it won't let the water vapor in the van from cooking and people get to the van sheet metal.

Gary

 

[MtDave]

Gary, what is your recommendation for insulating the roof ribs. I will be using the 1" polyiso on the ceiling and walls. I probably don't want to use the Great Stuff as that would be problematic when wiring. Or, would cutting a "V" groove in the polyiso be reasonable for running wire side to side?

 

[GaryBIS]

Gary, what is your recommendation for insulating the roof ribs. I will be using the 1" polyiso on the ceiling and walls. I probably don't want to use the Great Stuff as that would be problematic when wiring. Or, would cutting a "V" groove in the polyiso be reasonable for running wire side to side?

Hi Dave,
I used the Great Stuff Pro on my roof ribs. Part of this was that I have very little wiring in the roof ribs.

I suppose that Thinsulate might be good to stuff in the ribs that have wires, but not sure how easy it is to get in small quantities -- but, its such a small and confined area that the polyester fill might work fine?

Gary

 

[medicineman4040]

Ventilation is another reason many here do not go absolutely all the way to the floor (behind the black triangles) with the insulation. I think there are holes there for just this reason?

 

[El Guapo]

You can buy Thinsulate online at Outdoor Wilderness Fabrics. There's a few other online stores that I can't remember right now.

 

[Roblee]

I got pool noodles really cheap in fall. sliced them lengthwise and fed them behind the black triangles. They can't absorb water and don't pack tight so there is air movement. Given all the thermal bridging in that area I now doubt this does much for insulation. I also doubt they will harm.