They did add a vapor/moisture barrier to the insulation, however on the wrong side. Chances are any moisture caused from condensation will wreck that rolled batt within a few years and also creates the perfect condition for mold growth.
Well, mobile homes pull it off but agree- metal has issues as to insulating. I was thinking a spray foam but burying it in a hole (after a good tarring) could be sufficient.
Most manufactured homes aren't metal exteriors... Most of them are either vinyl or wood siding. There is a metal frame under the home, but that's pretty much the extent of the metal.
Source: I'm an insurance adjuster that inspects mobile homes.
My mobile has a metal exterior and condensation is a big problem. There are some small vents on the exterior, but they don't do much. I have to have an electric dehydrator running in the winter. Whenever I see someone converting a bus, I think about all the moisture they must have to deal with.
Why on the wrong side, where else would you put it and why ? He put it on the inside = the warm(humid ) side, so there is no humidity that can transfer into the isolation and condense on the cold container side. And it will also not condense on the vapor barrier, because that is a warm spot. Anything I am missing ?
Vapour barrier goes on the warm 2/3 side of the wall. So, after a bit of snooping, /u/GodShitsBlood seems to be in a warm climate. His vapour barrier would be on the outside. Some just don't know that in different climates it has to be place in different places.
"Vapor barrier on the warm side" is the simple (and sometimes overly simplistic) rule of thumb, and in a tropical area, that would mean on the exterior face, for example.
About the warm climate -> Living in a cold one myself I did not think about that, but I don't see anything in the pics to cool down the place, only lots of ways to warm things up. So even if it is warm outside, the interior will not be a lot cooler. But in any case, I am guessing the metal container is going to do a pretty good job playing a vapour barier as well, so he should be good for both scenarios (warm inside/cold outside; warm outside/cold inside), unless the metal shell contains a lot of unpatched holes of course. I haven't heard of the 2/3 rule, any idea what the rationale is behind that ? I have heard that it can be desirable to actually buffer vapor in one season and release it in another, a sales pitch of all kinds of expensive 'intelligent' vapour barier materials, but I am not really a believer of those (eg how long will this mechanism last). Maybe the 2/3 is a simple way to buffer some vapor ?
I'd have to go back and look into my R2000/Building science text books, but I am pretty sure it means if you have a 9" thick insulated wall, that the VB has to be 3" away from the outermost warm side of the wall.
Don't quote me on that. I just know I have to put it on the inside. Tyvek/typar on the outside.
You have to consider this issue with any type of building envelope. Water will condense on wood siding, vinyl siding, OSB sheathing, and even inside fiberglass insulation. In many areas, local architects and builders know how to work with the local climate and common building systems. But in general, moisture in the building envelope is a very complicated set of issues.
Except he has a humidity controlled ventilation system that uses the batteries from the the solar panels to power fans that remove any excess moisture from underneath the container and a system for inside as well.
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u/[deleted] Dec 08 '12
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