Greenhouses, Sheds and Sun Rooms - Water-sealing cinderblock base wall?

Hello again,

I've recently had to tear out two walls worth of drywall after water damage from a leaking sunroom led to visible mold. When I stripped out the drywall I found the base wall -- the roughly 3-foot high permament foundation that the sunroom skeleton was built on top of -- was built of cinderblock and that the cinderblock was weeping badly; but for a few dry spots the concrete was dark with moisture.

This base wall is capped with a wooden 2x6 as the stud foundation and then the sunroom support beams were built on top of that; the flashing on both the inside and outside of the base cap is losing its seal and allowing water into the base wall.

So what I need are some good ideas for how to seal this thing up again. Is there a concrete/cinderblock sealant I can use before re-drywalling that will prevent this porous weeping against the back of the drywall? (The old drywall was attached to the concrete by 1/2 " wooden furring strips, which were soaked and rotting.) Is there some sort of plastic sheeting or weatherproofing I should lay in between the cinderblock and drywall? I'd also like to find some sort of gel-like expandable insulation or caulking that I could blow into the base cap below the flashing, where the wall and sunroom frame meet, that would expand into all those nooks and crannies and seal the thing up tight.

Any thoughts?

Thanks!! This is a fantastic forum!

-cdm