Insulating concrete basement walls with closed cell spray foam

This is a homeowner's question posted to a building science forum, not a settled answer, so there's no expert guidance to pass along yet. The person asking wants to insulate poured concrete basement walls with closed cell spray foam while using as little wall space as possible, and they're wondering how to frame the wall afterward, including whether pressure-treated wood can touch the concrete directly.

These are common questions for anyone finishing a basement. Spray foam insulation is popular for basement walls because it also acts as a vapor barrier and air seal in one step, and closed cell foam in particular resists moisture better than open cell versions, which matters against concrete that can wick dampness. The framing question comes up because building a stud wall in front of the foam takes up floor space, and some people want to know if there's a way to save room, or whether the wood itself needs a moisture barrier if it touches the foundation.

At this point, no answers had been posted, so there is no specific method, product recommendation, or code guidance to report yet. Anyone tackling a similar basement project will run into the same tradeoffs between insulation thickness, usable floor space, and how to detail the wood-to-concrete connection safely.