A vapor barrier on both sides of the insulation will trap moisture in the insulation, not good. But there should be a 6MM barrier on the concrete walls. I prefer to use rigid EPS foamboard, insulation and vapor barrier in one.
Not overkill but wrong. As posted a double barrier. You need to stop moisture from the concrete wall into the basement. This can be done with rigid insulation against the slab. never use batt insulation for this. No vapor barrier should be used in the wall. The foam board provides a vapor retarder at the concrete wall side and the kraft face insulation (to the inside surface) provides a vapor retarder for moisture moving from the warmer inside air to the colder outside wall. Read the articles on www.buildingscience.com
Use kraft faced insulation of the batt insulation if you insist on using this. Maybe due to costs.Bob After reading the building science article it seems the second senario in the above is exactly what they are showing in fig14. Am I missing something when you say it's better but it will fail. How do you improve scene 2 . I am just following this because I am in the thinking process of framing and insulating also.
You are 100% right, not what I was trying to say. Foam in this situation is to provide a capillary break just like the foam board on the concrete wall.Bob, you may want to clarify this: "Use foundation sill insulation under the sole plate. This will allow air to flow into and out of the wall space you need to provide."
Sill sealers are to seal the air and moisture out from the living space. They don't allow air through them. Be safe, GBR