insulating where stud wall is built away from poured wall
Greetings from a long-time kitchen/bath lurker/poster. It's time to tackle the basement. I've been pouring through all the insulation threads I can find (XPS ones especially) and I can't find one piece of information. I've seen how to handle channelled XPS with furring strips and a stud wall directly adjacent to XPS, but how does one insulate properly where the stud wall will be built 9 or so inches from the poured concrete wall? I think maybe I read that the air space will invite moisture, and I don't see where a foot of insulation would be a reasonable answer. If it matters I'm in Portland, OR, and my basement is 75% below grade. The basement stays 62-65 degrees year-round and despite the fact that it rains a lot it has only seen water infiltration once in a single crack when the timer on my drip irrigation broke and the spigot basically ran non-stop for a week. However, I can't say that's true for the 83 years the house stood before I moved into it.
Thanks for the guidance,