# Vapor barrier in header area/between joists



## concretemasonry (Oct 10, 2006)

What makes you think you have to have a vapor barrier? - Since headers are over doors and windowa, you may dealing with two different conditioned spaces and not the usual situation between inside heating areas and the outside cold/unconditioned space.

If you are talking about the area inside a rim joist over a foundation wall, then a vapor barrier may be good on the warm side of the insulation if you are really concerned. In this case, immediately stuffing 1 1/2" thick precut extruded polystyrenr insulation between the joists immediately after you have foamed for air infiltration works well since the foam also acts as a adhesive. Then you can stuff in the pink junk to make yourself feel better. - After that, treat it like the rest of the basement if you are finishing off the space.

Between upstairs and downstairs, the difference in relatively humidity is really not much and the temperature difference is really minimal also. - You may be creating problems by micro-managing the details.

Dick


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## smorgdonkey (Sep 22, 2008)

Ok...maybe I am using the wrong terminology(?)...one of the upgrades suggested by my energy efficiency evaluation was to treat the 'header' area of the house. The header was defined as the part where the wooden structure meets the concrete basement. Directly above that are the floor joists and of course the bottom of the floor material.

I have insulated the open spaces on top of the foundation and I am thinking about enclosing those areas with the vapor barrier...just not sure how I should proceed as far as methods and such. Everything I have read says vapor barrier is the natural next step so that condensation doesn't become an issue.


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## smorgdonkey (Sep 22, 2008)

Here is a diagram of the areas that I am referring to:









For the most part where the 3 points to...


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## smorgdonkey (Sep 22, 2008)

No insight or ideas?


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## Maintenance 6 (Feb 26, 2008)

Use kraftfaced fiberglass, snug fit or cut poly to fit over unfaced. Anytime I've ever done it, I cut a strip of poly an inch or so taller than the cavity, stapled it to bottom plate and the joists. Then went along with a razor knife and sliced down the middle of the joist and pushed it up into the space and stapled it.


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## 4just1don (Jun 13, 2008)

My suggestion is to get foam insulation sprayed in that whole location,,,it seals cracks,adheres and stops any leaky crack all at once AND gives good r-values. I have tried using fiberglass and the wind still blows thru and around them,,,no great way of sealing all that,,,specially on a leaky drafty OLD house and a brand new house will be old before ya know it!!


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## smorgdonkey (Sep 22, 2008)

4just1don said:


> My suggestion is to get foam insulation sprayed in that whole location,,,it seals cracks,adheres and stops any leaky crack all at once AND gives good r-values. I have tried using fiberglass and the wind still blows thru and around them,,,no great way of sealing all that,,,specially on a leaky drafty OLD house and a brand new house will be old before ya know it!!


Good suggestion but it is already fiberglassed and there aren't leaks for wind to blow through.

It looks like poly and a knife are going to get a lot of time together...


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