Vapour Barrier?

[demtears]

Working on my floor and will be Insulating, and it just popped into my head, Is a vapour barrier necessary or needed? I will be using my teardrop in the winter as well as summer camping, have others used a vapour barrier during construction? I did a search and didn't come across any posts has there been any posts on this.

[madjack]

...a few have used it but don't see it as needed...in a well sealed tear, your breath will add more vapor than anything else...
madjack

[demtears]

Thanks for the quick reply madjack. I quess my concern is during winter camping using a portable heater inside combined with the cold air outside if there would be any moisture buildup between my walls and ceiling, and was curious if a vapour barrier would help or overkill.

[madjack]

Darrin, we have the exact opposite problem...air conditioning the inside while it is hot and extremely humid outside...my own personal opinion is that it would be overkill but then we do a lot of that when building our campers anyway...we did seal all wood...inside/outside/covered/exposed...as an extra bit of insurance...
madjack

[zapj]

Madjack, what would you recommend doing with the plastic film on the Styrofoam insulation panels? Leave it on or take it off and if left on would you place it on the exterior wall or interior on a sandwich frame? I have 1-1/2" thick walls and plan on using double 3/4" panels.

[davefullmer]

Darren,

If I remember correctly, when I lived in Michigan, we had to use humidifiers in the winter time to put moisture in our homes. The heated area dried up all the natural moisture and created a too dry situation.

Dave

[starleen2]

If you are using Styrofoam insulation, then vapors should not be able to pass through. It is the water vapor that passes through the fiberglass medium and condense on the other side that gives so many problems. Since Styrofoam is not easily penetrated by water vapor, then you should have no problem. I would use aluminum tape to seal around the joints and seams to keep the air transfer between sides to a minimum.

[madjack]

Madjack, what would you recommend doing with the plastic film on the Styrofoam insulation panels? Leave it on or take it off and if left on would you place it on the exterior wall or interior on a sandwich frame? I have 1-1/2" thick walls and plan on using double 3/4" panels.

I's leave it on and place it to the outside and rely on ventilation to handle any excessive interior moisture...because of the minimal volume of a TD, you should never sleep in on that is completely enclosed...always leave a little ventilation going on for fresh air...you certainly don't wanna wake up all purple and red!!!!!!!
madjack

[demtears]

Thanks for the comments I will be starting my Insulation on my floor, and then onto my walls. But I have a new problem went into are local Home Depot here in Canada and they do not stock 3/4 inch pink Styrofoam. They have 1/2 inch and 1 inch but not the 3/4 inch that I was going to use, does the Home Depot carry this in the US or do I go to Lowes I will be looking around locally at other lumber yards and if not will be crossing the border to locate the 3/4 board that will be needed. Thats the nice thing living so close to the US border if you cant locate it in Canada it takes me 10 minutes (if the bridge isn't busy) to be shopping in a whole other country.

[madjack]

...sometimes, the 3/4 can be hard to find...one option is to use the1/2" with a layer of Foil-Bubble-Foil on the outside...if you are not familiar with F-B-F, it is usually found in the section with roll(it comes in rolls as well) insulation
madjack

[demtears]

madjack you are a mind reader! That was going to be my next question, I did look at that, if I glued the 1/4 inch bubble foil to the 1/2 foam board do you think I would lose any strength in my walls?

[zapj]

Thanks madjack I'm glad to hear your opion because that is the way I insulated the floor. I needed confirmation before I used the same method on the walls and roof. Demtears, I found my 3/4" sheets of Styrofoam at Lowe's 6 months ago and hope when I need to by some more they still stock that size.

[madjack]

...glued or not, you willnot get any structural strength outta F-B-F...all it consists of is tin foil and bubble wrap...if you are gluing an inner and outer skin to stick framing, this should not be a problem....
madjack