Below is a simplified matrix of spaces that we typically start with. For the purposes of this post, I have entered relatively liberal square foot prices based on core and shell construction hovering around $100/sq.ft. with finishes between $40 and $60/sq.ft..or the purposes of this post, I have entered relatively liberal square foot prices based on core and shell construction hovering around $100/sq.ft. with finishes between $40 and $60/sq.ft..