The share a builder adds to carpet or built-up area to reach super area. The higher it is, the less of what you pay for is inside your home.
Guide
Three numbers describe the same flat and only one of them is floor you can stand on. How they differ, and which to ask for first.
Work it out as super area divided by carpet area, minus one: 1,300 sq ft of super area on 1,000 sq ft of carpet is 30% loading. Compare it between projects rather than against a 'normal' figure.