Twin stringer undermount stairs

For additional transparency, the mono stringer is replaced with two thin (5 / 8”) under mount stringers.

By default, the stringers are 6” apart and are usually placed at the centre of the staircase. For a more dramatic look, they may be placed off centre. If they are off centre, long flights can twist too much, but that issue can be remedied with a few (almost) invisible pins to the side wall.

The metal step plates are mechanically secured to the stringers and a walking surface board is glued on top.

The walking surface boards are usually ¾” thick hardwood but can be made of other materials such as tile or concrete.

If desired, the floating effect can be accentuated with box wood steps. Because box steps are more massive than the tiny stringers, the stringers become inconspicuous.