Originally Posted By: jlybolt This post was automatically imported from our archived forum.
Does anyone have any good information on vapor bariers and when and were required to install in crawl spaces? Are vapor barier required under mobile homes? Any help would be appreciated.
Originally Posted By: dvalley This post was automatically imported from our archived forum.
As Bruce stated, different geographical areas utilize different methods.
In my area, I want to see vapor barriers over any/all dirt crawlspaces. The poly barrier should be overlapped 12" at the seams and secured with contractors tape. The ends of the poly barriers should run up the bearing walls.
As for mobile homes in my area, I want to see a plastic vapor retarder attached to every subfloor area. The floors will rot and fall apart without a vapor retarder.
Originally Posted By: clawrenson This post was automatically imported from our archived forum.
A good place to start is possibly using the building code. We don’t quote code, but the code provides the basis for accepted construction practice or minimum building standard.
The "ground cover" generally reduces the moisture levels and potential for destruction of crawl space components such as wood floor joists, sill plates, etc.
Originally Posted By: jsieg This post was automatically imported from our archived forum.
The first house I owned had a crawl space under it. I contacter Owens Corning… you know the pink stuff, with the Pink Panther on their packages. The tech. rep. there told me that the perfered way to insulate a dirt floor non-conditioned crawl space was:
1. heavy black plastic vapor barrior on the floor, overlap sections by 12" and up any walls 12". Secure any overlaps with high qualith duct tape will be fine.
2. Run insulation verticaly on the exterior walls as high as it can go, down the wall and continue along the floor another 24" to cover the horizontal frost line.
He said that anything more would be a waste. He also told me that he felt that having good insulation in the walls was more inportant in my area then in the ceiling due to blowing wind causes walls to loose more heat than the heat loss through the roof. (more surface area and windows than most roofs)
Originally Posted By: rmeyers This post was automatically imported from our archived forum.
James,
Regardless of what local requirements may say, I've found vapor barriers are critical!!!
Iv'e inspected a few moble homes with steel frames under them. In general, I have found the vapor barrier to be critical in protecting the structure. The frames in most cases were heavily rusted, one to the point of failure of several cantilevered elements.
The moisture under the trailers had also seriously deteriorated the floor insulation and in some cases, affected the floors above.
Iv'e seen moisture from crawl spaces permeate throughout structures and cause condensation along ceiling edges (staining & ghosting) and also condense and form frost in attics on plywood and nail points of conventional framing.
Hope these comments highlite the importance of vapor barriers / ground covers.
HAVE A GREAT DAY!!!   
Originally Posted By: dspencer This post was automatically imported from our archived forum.
I do not think the conflict has been so much with the vapor barriors but with the venting of crawlspaces. A VAPOR BARRIOR is a MUST. Vapor barriors should also be used before pouring of concrete slabs
