Latest Discussions : HVAC


07:48PM | 10/15/05
Member Since: 08/17/04
16 lifetime posts
I installed a new window in a bedroom, and have a question on how it was insulated. Currently, the walls are 2x3's. There is R13 between the studs, with vapor barrier. then there is 3/8 inch plywood, followed by a layer of tar paper. i then put a layer of plastic on the wall (maybe 5 feet wide(the area that needed to be reworked)), followed by 1 inch foamular, then the wood siding on top of that.

The question I have is, should that sheet of plastic be sandwiched between the tar paper and foam? I would have put tyvek in it's place, but that is very expensive for the very small amount I need.

I guess I am wondering, will this sheet of plastic cause the wall to rot over time due to condensation trapped between the plastic on the outside and the vapor barrier on the inside?? I live in WI, and the climate changes drastically.



04:06AM | 10/20/05
Member Since: 01/28/03
693 lifetime posts
Plastic sheathing should never be used on the outside of the wall over sheathing.

It will trap condensed moisture against the house causing your wood sheathing to rot along with the studs in a very short period of time.

Even with the tar paprt left in place, youwill still get the same result because tar paper is somewhat pourous to water.

You really need to think about removing this plastic sheeting because rot is a guarantee the way you did this.

And by the way, housewrap or felt paper or plastic is never used in conjunction with exterior rigid foam insulation.

Remove the plastic because it's going to create a lot of problems.


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