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So I've got rigid insulation up, and that's all fine. But my van is gray, and in the summertime, the remaining exposed metal becomes extremely hot, and now that it's winter, it becomes extremely cold. I asked about this before, and the standard advice seemed to be to put thinsulate in the channels. But I'm confused about that -- it doesn't seem like it would solve the problem, because the metal is still connected to the outside of the van, so it will still get hot or cold. It seems like you'd need to cover the metal completely somehow to have an even semi-effective solution -- and that sounds hard to me. Any suggestions?
 

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Cover it - filling them in is a waste of time.
That sounds like a good idea. However, filling them would at least keep ambient air from reaching the exposed metal and should be effective in maintaining desired interior temperature. Also, since our vans are "glued" together in many locations, that glue should act as some sort of thermal break between exterior metal and the ribs. If all else fails and the ribs are still too hot, paint your van white.
 

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Having a thermal bridge was pointed out to me recently and I am coming up with no easy solutions. Everything seems to result in lost headroom or added expense.
 

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Had a wacky idea about this. Not sure about its practicality and efficacy. Maybe Garybis will chime in on this.

What about introducing thermal mass materials into these spaces? Don't think you'll solve the conduction problem without loss of headroom or elbow room. But maybe you could make these areas work for you by storing or at least attenuating heat. This is typically done in the floor in passive solar homes, but these spaces are heat sinks anyway, so what the heck?

Not sure what you'd use for material. Most of this stuff is heavy. Water comes to mind, maybe in PVC pipes if you could get them inbetween the ribs. Sand inside of PVC pipes also comes to mind. Phase change materials like paraffin or salts might also work. All bad news if they leak, and things might slosh or rattle around. Might be able to attenuate this with gelling or other agents.
 

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I would suggest that most of you are way overthinking this! I have the felling that many people just want to think about what they should do rather than just build their van out and use it. Nothing wrong with that, but as they say "That dead horse ain’t gonna get up no matter how much you beat it" ;)
 

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I would suggest that most of you are way overthinking this! I have the felling that many people just want to think about what they should do rather than just build their van out and use it. Nothing wrong with that, but as they say "That dead horse ain’t gonna get up no matter how much you beat it" ;)
Yeah, probably right. I thought about it a bit more and slept on it, and decided that you couldn't add enough thermal mass to overcome all the metal in the van.

This link explains the folly of such ideas: https://passipedia.org/planning/the..._works/thermal_protection_vs._thermal_storage

Basically we're doomed... why insulate at all if you can't address thermal bridging. ;). You can't cheat entropy; the universe is expanding. That sort of stuff.

I've been laid-up for a couple of weeks with a back injury, so I can't do much but light duty work on my van. I think I've actually done pretty well in the overthinking department considering...
 

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Ah KOV we can always count on you to talk us down from the edge


Sent from my iPhone using Tapatalk
 

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So I've got rigid insulation up, and that's all fine. But my van is gray, and in the summertime, the remaining exposed metal becomes extremely hot, and now that it's winter, it becomes extremely cold. I asked about this before, and the standard advice seemed to be to put thinsulate in the channels. But I'm confused about that -- it doesn't seem like it would solve the problem, because the metal is still connected to the outside of the van, so it will still get hot or cold. It seems like you'd need to cover the metal completely somehow to have an even semi-effective solution -- and that sounds hard to me. Any suggestions?
Our experience has shown that filling those areas with Thinsulate does help a lot. Thermal bridging does happen but remember that the van skin is bonded to the structure with thick adhesive that does act as a thermal break. Much of the cold and hot is also being transferred by the enclosed air. Keeping that air from moving helps reduce the thermal losses & gains.

What I believe is happening:

In hot/sunny conditions (especially darker vans) the air in the enclosed spaces gets hot, expands and can start to flow like in a chimney where hot air expelled at the top and replaced with cooler air at the bottom. Thinsulate in the enclosed spaces reduces this effect by reducing the circulation.

In cold weather these same areas can flow backwards (downwards) by pulling in warm living space air at the top; that air cools, flows downward and out of the space and back into the van at the bottom.

Our recommendation would be to get some Thinsulate(TM) in there. The cost and effort is minimal.

I am sure there will be disagreement. But that mostly comes from the folks who have used other insulation methods that are not conducive to filling cavities and thus feel a need to defend their practices. We base our methods on the combined experience of 3M, ourselves and hundreds of satisfied customers.

All the best,
Hein
DIYvan.com
 

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Oh [email protected], now two good conflicting arguments are presented and both are obviously right. I faced this too and used GaryBIS’s calculator to resolve the question. What is enough? My main concern was running my Espar at about freezing and having it not shut down and restart, but run at it’s lowest setting quietly. The calculator gave me an answer and the 1” polyiso was perfect. I covered a lot of metal ribs with nothing more than fabric or plastic panels. The results have been tested and Gary’s calculator was correct. I did fill some ribs, but many are not. Wouldn’t this be a way to decide? Hein's argument that cold air or hot falls and rises in the ribs is important to avoid a cold air stream coming down on you when you are sitting or whatever. I’d advocate for some fill or breaks but not go nuts.

See:https://www.builditsolar.com/References/Calculators/VanHeatLoss/VanHeatLoss.htm
 

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I try my best and even better - I’m not trying to sell anyone anything ;)
Not really,

You are promoting your ideas and methods. Which is great.
Maybe not for money but there is value and you are selling it.

Regardless, that's no reason to be passively aggressive towards me
when what we suggest does not follow your line of thinking.

P.S.
I thought I had deleted this post shortly after writing it figuring it was probably not a good idea to draw ire from super moderator, KOV. He apparently saw fit to restore my deleted post and then quote it to further his personal attack. Oh, sigh,,,, Good to have thick skin around here.
 

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Our experience has shown that filling those areas with Thinsulate does help a lot. Thermal bridging does happen but remember that the van skin is bonded to the structure with thick adhesive that does act as a thermal break. Much of the cold and hot is also being transferred by the enclosed air. Keeping that air from moving helps reduce the thermal losses & gains.

What I believe is happening:

In hot/sunny conditions (especially darker vans) the air in the enclosed spaces gets hot, expands and can start to flow like in a chimney where hot air expelled at the top and replaced with cooler air at the bottom. Thinsulate in the enclosed spaces reduces this effect by reducing the circulation.

In cold weather these same areas can flow backwards (downwards) by pulling in warm living space air at the top; that air cools, flows downward and out of the space and back into the van at the bottom.

Our recommendation would be to get some Thinsulate(TM) in there. The cost and effort is minimal.

I am sure there will be disagreement. But that mostly comes from the folks who have used other insulation methods that are not conducive to filling cavities and thus feel a need to defend their practices. We base our methods on the combined experience of 3M, ourselves and hundreds of satisfied customers.
it sounds like you're trying to have it both ways - if thermal bridging isn't much of an issue, than there wouldn't be (much of) an issue with the channels acting like a chimney - the air would / should act similarly to other convective currents in the van, right? it would only be like a chimney if there were significant differences compared to the air outside the channels. and if convection in the channels were the primary concern, seems like stuffing some material in one or two spots would take care of that?

i ask not as someone defending how i've done it - i haven't done anything yet, and am still trying to decide what to do on the walls and i'm just (an engineer, probably overthinking it) looking for answers.

i find your arguments regarding sound attenuation more convincing. :D

i see this argument with hein and other posters (some of the same posters) in multiple forums - it would really be awesome if he went out and collected some data on this. :D
 

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Yet another option: We insulated with poly-iso and low-expansion Great Stuff Foam for Doors & Windows. After confirming ourselves that this particular foam cures soft and spongy, we test-filled the short vertical rib-channels around the high roof extension. As expected, no sign of body deformation at all. We also test-filled the roof ribs with Thermawrap (similar to Thinsulate). The latter went pretty fast with two people and a fishing wire, but foam was even quicker with just one person. On the downside, D&W foam might be a little more expensive by volume, and it negates future access for wires, etc. But, it's still a viable option in some situations.
 

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Not really,

You are promoting your ideas and methods. Which is great.
Maybe not for money but there is value and you are selling it.

Regardless, that's no reason to be passively aggressive towards me
when what we suggest does not follow your line of thinking.


Ah, where to start?
I suppose the best place is with you personally. Although I try very hard to keep personalities out of this forum sometimes it just isn’t possible or even advisable.
As a businessman who makes and sells personalized products (so to speak) you have a vested interest in selling as much product to as many people at the highest price and the lowest cost per sale. One has to suspect that is why posting on this forum, the Transit forum and the Sprinter forum is so important to you. Whenever and wherever you can get free advertising at someone else’s expense why not? Selling on Amazon & eBay isn’t cheap and making a few casual posts on these forums suggesting products you just happen to sell or manufacture is free so why not?
Why not? Because when someone sets themselves up as the go to, expert guy on just about everything and just happens to have a financial interest in all of their recommendations to people, the value of their expertise become questionable.
I’ve pointed out in the past that for a miserly $40 anyone can become a lifetime member of the forum and help support it but even that appears to be "too much" when you can do it for nothing - that alone tells me and others an awful lot about how you view the forum.

Now, back on the subject. Does filling in the voids in the channels, ribs, etc with insulation make the van anymore comfortable? Some swear it does others (including myself) say it certainly doesn’t hurt but the value of doing it is basically next to nothing if you’re going to cover it with anything, even something a simple as a piece of fabric or wood. I speak from past experience (and I have lots of it) and, most importantly, I have absolutely nothing to gain from from anything I post here other than helping others who may have less experience.
People may not agree with everything I post or what others post and that is perfectly ok and even good BUT it is very important to expose people to more than one point of view. There are many ways of doing the same thing (as others here have discovered) and the best way is the one that makes you and your wallet feel good about what you are doing.
 
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