Leveling floor, overlapping existing drywall

[soparklion11]

I stupidly framed out my basement and put up drywall, which looks great. I then realized that I should level the floor - it drops 3-4" over 12' and it isn't flat, either. I want to use concrete to level the floor so that I have more flooring options. My drywall ends ~1" off of the floor so that it doesn't wick water and I have a membrane under the sill piece. Leveling the floor would place the level of the concrete high enough to overlap and contact the bottom 2-3" of drywall.

If I have 2-3" of concrete against the drywall, I will need a moisture barrier. What can I place on the bottom of the wall to stop moisture from wicking into the drywall? Or do I rip off the bottom of the wall? If I rip the bottom off of the wall, do I need to do anything to support the bottom of the drywall - it seems that it would crack. Or do I tear down my new wall and level the floor underneath it?

The basement has an interior French drain and there is a floor drain in an adjacent room. Plastic over the floor shows moisture due to a high water table, but there has never been water in the sump for the French drain.

 

[soparklion11]

Bump?

 

[Ernesto]

Tricky issue. I would cut off more sheetrock and add some CBU on the bottom, seal it up with Mapei Aqua-Defense and fiber tape along the bottom much like a shower pan.

http://www.mapei.com/US-EN/Tile-&-S...aterproofing-Membranes/Mapelastic-AquaDefense

 

[highup]

That sounds good. Cut the CBU so it's 1/2" or so higher than you need it. Self levleing concretes will flow through small voids. So if you plan to use a self leveling product, be sure the corners and edges of everything are sealed and caulked well.......... as if it's a swimming pool.