Closed Stringer Flight

By Huu Khanh Nguyen · Updated October 28, 2026 · stair, flight

A straight stair flight with a housed string on each side that encloses the treads and, optionally, the riser boards.

Parameters

Name	Default	Unit
Number of risers (the flight has risers - 1 treads)	13
Riser height	175	mm
Going, nosing to nosing	250	mm
Overall width across the strings	1000	mm
Nosing overhang of the treads beyond the riser line (y)	25	mm
Tread thickness (z)	40	mm
Riser boards	true
Riser board thickness	19	mm
String thickness across the width (x)	30	mm
Housing depth of the treads and risers in the string (x)	12	mm
String margin above the nosing line and below the lowest housing	50	mm
Finish of strings and risers	white
Width	width	mm
Height	risers * rise	mm