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Dirtbag van insulation

Original Post
Michael DeNicola · · Unknown Hometown · Joined Feb 2014 · Points: 0

So this weekend I plan to purchase my Sprinter and begin the long and rewarding process of converting it into a camper. In all my excitement I have started researching insulation methods but I've ran into a lot of conflicting information and it's unclear to me what I really need to do to stay warm, cool, and protect the van itself from rust damage. I'm hoping to find some more experienced van dwellers to help me make sense of all this. To provide some background info on my insulation needs I currently live on the Southern California coast and intend to travel throughout the southwest, likely avoiding extremely cold temperatures (<20 F in my book).

I'll start with the most controversial topic. Moisture barriers. Several blogs/ articles I've found insist that one must put in some kind of moisture barrier to prevent moisture build up that will ultimately cause rust and ruin the van. The most common method to prevent this is to use spray adhesive to line the walls with a material like reflectix and then fill in gaps/ ribs with expanding foam insulation. This mostly makes sense to me but it still seems like you would run the risk of their being gaps in the insulation where moisture could accumulate and actually have a harder time evaporating thus leading to faster corrosion.

This leads me to my second point of how necessary is a moisture barrier really? Say I put in nothing and just stick with the factory installed plastic paneling (uncomfortable I know but cheap and easy), it seems like that would allow any moisture that accumulates over night to evaporate relatively quickly before any corrosion could really get going once the exterior air warms up. Thoughts on this?

Lastly comes the insulation technique that seems to make the most sense to me at this time. Why not use a powerful tape to attach thinsulate to the walls, thread it through the ribs then cover it with my paneling of choice? My thinking is that it would:

* Do a decent job of insulating since it has an R value of ~3

* Wick moisture away from the metal since it is a fluffy synthetic fabric and allow it to dry

* Not be likely to host mold or insects (like wool or denim).

Doing this would also have the added advantage of being much less permanent than other methods since it does not involve large amounts of adhesive or filling in small spaces with foam.

Any and all advice is appreciated!

-Hobo Mike

Hobo Greg · · My Van · Joined Mar 2016 · Points: 160

Hobo Mike?? What is this bullshit?!

Hobo Greg · · My Van · Joined Mar 2016 · Points: 160

Either way let us know, I'm going to be insulating my van soon.

Spencer Ringwood · · Somerville, MA · Joined Aug 2016 · Points: 0

The strengthening ribs that provide rigidity throughout the body are attached using spot welds and the interior of these ribs (which are essentially hollow tubes) are generally bare steel. A light surface oxidation will develop but it should't cause major issues; the only realistic way to be sure this never occurs would be to drill holes allowing access to the interior of these hollow spaced to apply rust inhibitors to the bare sections, like paint or waxoil. This is completely unnecessary. 

Condensation doesn't present much threat to the interior panels; the paint is tough and won't see any kind of surface wear when it's behind insulation and finish panelling. A vent that allows moisture to escape the space between the finish panelling and the body of the van would be a nice touch. I wonder how effective they would be if you do a good job insulting the van and I'm not sure if that would negatively effect the insulating properties.

At any rate, assuming condensation is a big problem, the best approach would be to seal the interior of the van's body using a thick epoxy paint or having professional bedliner sprayed on the interior before insulating. Trying to create a moisture barrier that keeps condensation from entering the insulating compartment is whole lot of work that isn't going to give you the results you're looking for.

The best approach, in my opinion, would be to insulate the van using hard foam insulation. It is easy to work with to get a perfect fit for each panel and is easily removable. This will allow you to inspect the condition of the body and make repairs as needed.

Expanding polyurethane foam insulation creates an open cell foam-  it's a big sponge. This will hold moisture against the body of the van and create rust issues. 

Guideline #1: Don't be a jerk.

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