hollow architecture

I wonder if we have hit the point of diminishing marginal returns for efficiency in material use in buildings? An old masonry structure like a cathedral might have as much as 30% of its floor area given over to structure. A modern box store might have as little as 10%. Given new standards for energy performance, we might start devoting a little more area to exterior walls to improve the quality of the thermal barrier. I'm in favor of that.

Also, I think that efficiency in architecture is a curious issue. The average office worker takes up about 8 sq. feet in a chair and gets another 12 s.f. for a desk. Conventional programming guidelines typically allocate 250+ gross s.f. for each worker to account for circulation, common spaces, structure and plain old elbow room. An ignorant bean counter might look to squeeze more productivity out of a building by limiting area per worker, but I doubt that such measure would realize improved workplace performance. I'm probably wrong about this and as punishment I'll be working in coffin sized cubicle next year.