RERA defines 'carpet area' as the net usable floor area of an apartment, excluding the area covered by external walls, exclusive balconies, or verandas. Build-up space is the sum of carpet area and what is occupied by exterior and interior walls, balconies, exterior staircases, and corridors. A super built-up area is the sum of the exclusive built-up area and those areas shared by all, like elevators, common corridors, staircases, clubhouses, etc. Having understood what carpet, built-up, and super built-up areas mean, you now know what to ask the seller when you buy a house.