Vapor Barrier

[Deleted]

Does anyone know of a good (less expensive) alternative to Tyvek for a vapor barrier. I hate the idea of buying a 9’ x150” roll and then have two/thirds of it sit in my garage for all eternity. I didn’t want a lot of seems, so I ‘m looking for something that will cover the roof in one piece. I know plastic is not a good alternative because it will not let the moister out so I don’t really want to go that route.

[idqrocks]

I think most vapor barrier is plastic and is installed on the interior side of the wall. Not sure how it will work in a camper with little to non insulation. I chose to put it up, and construct similar to a house. Seems to stay REALLY warm in cold weather.

Are you looking for an added protection for leaking? And not so much vapor barrier?

[schweetcruisers]

Apr 22, 2013 14:38:13 GMT -5 @smccusk said:

Does anyone know of a good (less expensive) alternative to Tyvek for a vapor barrier. I hate the idea of buying a 9’ x150” roll and then have two/thirds of it sit in my garage for all eternity. I didn’t want a lot of seems, so I ‘m looking for something that will cover the roof in one piece. I know plastic is not a good alternative because it will not let the moister out so I don’t really want to go that route.

You can sometimes find a remnant roll on Craigslist, also Lowes' sells a off brand that's about a $100.00. If you need to have a seam make sure to use the Tyvek brand tape.

[Deleted]

Another question, The insulation I installed is 3/4 foam with a foil backing on two sides. Do I even need a vapor barrier? Yes, it would be good for extra leak protection, but is it necessary.

Schweet...already checked craigslist...there is nothing right now, will check out lowes. There are people on ebay that sell 9' width by the linear foot @ $1.85 plf. What I need would still run about $100.

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[nomad]

I use Styrofoam blue housewrap on my construction jobs and I have used it in the Nomad. It has tiny perforated holes so I think its a little more breathable than the Tyvek. A 3'x100' roll cost about $20.00 at our lumber yard. It also comes in 6' and 9' long rolls

[mobiltec]

I use Roberts Unison from Home Depot. Comes in a roll for about $25. Might need one to two rolls depending if you do the sides or not. Unison is actually underlayment for laminant floors so you will find it in the flooring section. My website has videos on the installation but it's not rocket science. You just want to remember to start at the bottom and work up to the middle of the top. Do the same at the other end. The top piece overlaps both. So it's done the way you shingle a house so if moisture runs down inbetween it and the metal skin, it doesnt go inside the next layer. It also adds a little insulative qualities and some of that puffiness that I like to see on trailers with 4 or 6 inch breaks in the metal skin. Neat stuff.

[Deleted]

Mobiltec, Do you know if that material breathable on just a moisture block. What is appealing about using Tyvek is that it releases moisture coming from inside the camper as well as blocking from the outside. I'm not sure if that's a huge issue in these small campers...it seems like most of the moisture would exit via the less than air tight windows. I appreciate your insight.

[mobiltec]

Being that it is flooring underlayment it would just about have to be. You can see that one side is shiney and one side is dull so you want to make sure and put the shiney side up. There is also sticky back tape all along the leading edge so it will hold itself in place untill you go over it with a stapler. I put as few staples in as possible for obvious reasons.

Anyways yes. The shiney top will hold moister out away from the framing and insulation while the other side is just bare foam and will breath.