IS A VAPOR BARRIER NECESSARY? Vintage Camper Insulation Questions

This week I'm putting in the insulation on my 1956 Cal Craft rebuild and asking the question - Is a vapor barrier necessary? Does it do more harm than good? Let me know what you think in the comments!

[ProjectNineOaks]

Perfect timing on this video. I'm getting ready to putting insulation on my camper build in the coming weeks. I like your rigid foam idea. Thank you and keep it up!

[thisoldbelair]

It’s so fun watching this trailer come together. Nice work, looks amazing

[zanesutherland]

Curious other people’s thoughts, but I think what you’re doing is just fine. I think if the camper is sealed up well from the exterior and you are monitoring and controlling the moisture levels inside then hopefully condensation and moisture in your walls won’t be an issue. I’ve lived in my camper full time since September 2018. Mine is a 1988 Terry Resort 24ft with aluminum siding, wood framing, fiberglass insulation. I repaired any water damage and sealed it up really good. I have a humidity monitor inside and I make sure to keep in below 50% or there is a chance for mold to grow. Usually it stays between 25-34% humidity. I make sure to exhaust any steam, cover any boiling water. Keep the temperature constant in the winter so there isn’t extreme temperature fluctuations. I’ve got silica packets in all my cupboards, a couple bamboo charcoal humidity absorbers, like 6 small moisture absorber tubs you can get at the dollar tree. Also 2 of the Eva dry reusable dehumidifiers. A have a house size dehumidifier under my desk that I will also run if it rains outside and the humidity rises. I recently installed a cubic mini woodstove. I did it when it was freezing outside and probably 60°F inside. While I had the hole open in the roof I felt the underside of the metal. I don’t know if it was just then because it was exposed or it’s always been that way, but I could feel some moisture present on the metal. Not wet, not dripping or anything problematic, not enough to cause mold or anything; I could just detect it’s existence. So it’s important to control the humidity, because I bet if my humidity was high enough in the winter it would be raining condensation on the ceiling paneling from the underside of my roof and cause mold etc. But luckily it’s nice and dry :) no issues for me. The first camper I ever bought (a 1974) the guy had lived in it during the winter for over a year and didn’t control the moisture at all. It also leaked at all the seams. The roof beams, even where there wasn’t an actual leak, were covered with black mold from the condensation problem.

[michaelnelson]

I agree, no to the vapor barrier. As you said, it is more likely it would retain moisture, than it would prevent moisture from entering.

[dtmty]

make a video of the after a year with insulation, also if you can measure the heat inside and outside, would be great

[roar]

Typically, the vapor barrier should be on the warm side of the wall. In northern climates it's placed on the interior and in southern climates it's placed on the exterior. The reason for this; as temperature drops from the warm side to cold side, it can reach the dew point where moisture vapor would turn to water droplets on an impermeable layer. The moisture vapor needs to be able to flow towards the cool side and disperse. Not sure where you are located, but most likely you would be using the camper during the warmer times of the year. With that said, I would avoid using a vapor barrier so that any moisture vapor can readily transfer through the wall.

[barrydelljeremy]

Wool works the best. It releases moisture, isn't flammable, and of course warm. But it may be expensive idk i have so i use there wool so its free

[mrscrane]

Did you put those little spacers behind every single panel or just some of them?

[deborahfieldson]

So, I have a moisture question you might have insight into. I live in northern Calif, normally dry climate (think drought). I took my needs to be renovated 1968 camper out, the outside is in pretty good shape with the previous owner doing a good sealing job around the exterior, inside not so much...with rippling on the paneling and that's where my ugh, let's not go there. OK, so my question is, I went camping this wknd with temps in the low 40's and brief periods of rain. The interior walls were cold to touch, but everything fabric was damp, like very damp. The walls and metal parts weren't moist and I saw no indications of leaks. I only had small ceramic heaters and they were no match. My guess is more efficient insulation when I do the renovation and a better heat source, but how do you manage dampness or humidity? I've probably answered my own questions but, the interior dampness is just baffling. BTW, love your work.

[ckkern]

Did you put the bubble radiant barriar on ?

[jerrytalley]

I wonder if the foil type HVAC tape, it would seal the foam panels and could cover the wood?

[alexlindekugel]

most camper interiors that ive seen are vapor impermeable so vaper going threw interior to exterior shouldn't be a problem. and the thicker the wall insulation less likly for condensation. and considering how lose most camper exterior cladding is it should dry fast especially when driving down the road..

[kiyamanus]

I think it will retain moisture and drip down and sit on your framing but who knows should last just fine. Way better build than these 40k ultra light trailers with disposable styrofoam floors that start sagging.

[jerrytalley]

Have you looked at radiant barrier, would think that would do wonders to reflect the sun? One I used in my house was ATTIC FOIL. The reason I mentioned that is, it breathes, is super tough, and reasonable

[agentofficerthomasa.porter]

Yes your wood framing is 1 1/2 inch you use 1 1/2 inch insulation & wrap over this your vaper wall wrap over this. You want to apply glue before put'n the insulation board into place.