1. Yes – Great Stuff Pro works very well adhering it to concrete.
2. You figured this one out!
3. No – If you use a minimum of 1-1/2″ (2″ preferred) polystyrene insulation and seal it properly there’s no need for a vapor barrier.
4. Not mandatory – This is more of a concern when using 1-1/2″ foam plus fiberglass. If you go with 2″ of foam and skip the fiberglass then you can frame it tight.
5. Can you be more specific? Not sure what product you’re referring to.

Good luck!

I’m stumped on a few things, and I’m glad that I came across your site.

I want to frame the basement walls of my mid-1940s cape cod-style house, and so I’ve been reading books and gathering lots of information so that I can to make sure that I do it correctly. The last thing that I want going wrong is mold!

So far, I’ve painted my concrete block walls with two – three coats of waterproofing paint and a mold/mildew resistant sealer.
I’ve also installed a drycore subfloor, leaving a 1/4″ gap between the wall and the subfloor material.

The next part I’m not so sure about in regards to vapor/water barriers and insulation. In reading your posts, I have a few questions:
1) Can the polystyrene foam board be installed directly to the concrete wall?
2) Should the polystyrene foam board insulation be sealed somehow at the top and bottom?
3) After putting up the polystyrene foam board, should I still install a 6 mil plastic sheet between the foam board and studs or between the studs and drywall?
4) Should there still be a 1/2″ gap between the foam board and studs?
5) Would it be okay use a thermal guard insulation stapled to the studs instead of using a fiberglass insulation between the studs?

Any suggestions that you offer will be of great benefit, and will allow me to proceed with confidence!

hope this helps,
cheers,