My situation: My customer’s 80 year old house in central Illinois. Two sides of the gutted bathroom exposed to the prairie winds. Wind blows through the vinyl siding and foam backing. I decided to use Tyvek — actually Amoco’s housewrap — and put the wrap on the INSIDE of the stud bay. After that, kraft faced R-13 batts and 6 mil plastic over the batts followed by 1/2″ sheetrock. Well about 90 % of the wrap is up and I’m wondering —
Will I trap too much moisture?
Will it breathe enough?
Will I create mold? Or rot?
Is it better to just suffer the wind and lose a bit of insulation value and avoid the risk of mold or rot?
crawdaddyjack
Edited 12/31/2002 12:57:26 AM ET by crawdaddyjack
Replies
House Wrap has two surfaces. Make sure that the "This side outside" surface faces the outer wall surface. Moisture will migrate to the outside where it will dissipate. Think of this material as having umpteen million, micron size, one way valves per square foot that allow flow only in one direction. The next thought to keep in mind is that one way valves hang up from wear or damage. That fact is what brings in the argument in some camps that house wrap isn't worth the expense. I feel that the material is better than nothing at all, you are attempting to retard or at least slow down those 80 MPH prairie winds while still allowing moisture to escape from the inside of the wall. The material should be applied carefully and tapped and sealed with great care. Try to find a contractor to do that :-) Next, after insulation, the most important move to make, use a good quality "I like 6 mil thickness" vapor barrier which must be completely sealed to the inside stud surfaces "between the studs and the greenboard or cement board etc. You should also use the vapor barrier in the ceiling where a great percentage of vapor and heat escape.
You can find expanded information on your issues by locating <http://www.hud.gov> You will get some honest and good information on your project.
I hope the weather doesn't get to much colder for you while completing your project :-)