Plastic or tyvek?

[Wimperdink]

Just a quick question. I am rebuilding a 1962 or 64? Aloha canned ham trailer. I'm still in the process of insulating. I intend to cover this with some type of moisture barrier before putting the tin back up. Would you recommend using plastic sheeting or tyvek? Plastic I have, Tyvek I don't.

[48Rob]

Vapor barrier would go on the inside, between the paneling and insulation
(unless you are in an extremely dry, hot climate where the inside of the trailer is always air conditioned).
Tn. doesn't qualify...

If you have to put something on the outside, Tyvec is a much better choice than plastic, as it will allow trapped moisture to get out of the wall cavities.
If you put plastic on the outside, it can trap the moisture, causing more rot and mold problems.

Rob

[Wimperdink]

good point.... I was hoping that if there were any future leaks like what caused the need for this rebuild in the first place, that it would just roll off and down on the moisture barrier before touching wood. The windows in this trailer are the glass slats that don't seal worth a hoot so ventilation isn't an issue anyway.

[cracker39]

Vapor barrier would go on the inside, between the paneling and insulation
(unless you are in an extremely dry, hot climate where the inside of the trailer is always air conditioned).

Rob

Both here in Florida and in Maryland and Virginia (while I lived there), I've seen Tyvek installed on the outside of the framed walls before the siding went on.

Examples. I Googled "Photos Tyvek Installed" and they all look like these.

http://www.homesforourtroops.org/images/content/photos/large_16150.jpg
http://www.dflyonsconstruction.com/images/Tyvek_house_wrap.jpg
http://www.renaissancerestorations.com/portfolio/nharwood/nsiding1.jpg
http://www.bannisterhousetexas.com/images/P4270511_lg.jpg
http://www.kc0qir.com/blog/gallery/1/PC030033.JPG

[48Rob]

Dale,

I might be misunderstanding the reason you quoted part of my post?

Tyvec is not a vapor barrier, but plastic is.

The vapor barrier in normal climates goes inside the home, between the insulation and studs/framing to prevent the interior moisture from going through the insulation and or cavities and condensing on the back of the exterior wall.

Tyvec is designed to slow water and air penetration into the home past the siding.
Tyvec "breathes" that is, it allows moisture vapor through, but not heavy moisture like rain.
People in many states use it for that purpose, but it does not replace a moisture barrier, which does not allow anything, water vapor or air movement.

In some hot and humid states, builders may or may not choose to install a vapor barrier, due to concerns that there is just so much humidity in the air, that it is better to let the breeze "blow through the wall".
But in those cases, even Tyvec should be avoided as it will slow moisture release from wall cavities.

If I misunderstood your intent, I'm sorry.

Rob

[cracker39]

OK Rob, I probably did misunderstand. Yep, vapor barriers do go on thie inside of the wall. Sorry if I missed the point.

[48Rob]

Thanks Dale, I wasn't mad, just wanted to clarify.


Rob

[Wimperdink]

Just for sake of conversation, I went with your original post Rob and the tin is back on with nothing between the tin and the studs... My final deciding factor was that it was great like that for the first 50 years.... I'd be happy with 20 more.

[Off Grid Rving]

all this talk about tyvek.... any idea where I can get some tyvek scraps. I am need to sew a shell for my flip over ice shanty that im building for this winter. and I dont need a 100 dollar roll of tyvek heh

[halfdome, Danny]

all this talk about tyvek.... any idea where I can get some tyvek scraps. I am need to sew a shell for my flip over ice shanty that im building for this winter. and I dont need a 100 dollar roll of tyvek heh

Tyvek comes in 36" rolls (cheaper for a small job) and can be seamed with Tyvek tape. I did this on our home this summer. Easier to handle for one person. I screwed a closet pole to the building and rolled off the Tyvek like a large roll of paper towels. Very easy by yourself. Danny