I've been thinking alot about alternatives to SIPS and wondering one thing: when the topic of build-in-place exterior (to the frame) enclosures (i.e. 2x4 or x6 walls with sprayed foam or cellulose) is discussed, why is the spacing always so close? We all don't want our frames made redundant.

Am I missing something? Couldn't we build these frameworks minimally -- frame in windows and doors, add enough for sheathing (4' centers) attach it to the frame for stability, and insulate that? Reduce conductivity, reduce redundancy?

thanks,
matt