Staircase and Metal Tread The house’s stacked floors progress vertically from the communal basement, through the mixed-use mezzanine, to the private bedroom. Its staircase responds to these functions. Perforated folded steel steps between the ground level and mezzanine allow for greater access to sunlight. Between the mezzanine and upper level, solid folded steel stairs and partitions serve as the bedroom’s acoustic barrier.  Cleverly Stacked Floors Form a Roomy House On a Tight Lot by David Rudin