Calculated Industries 4090 User Manual

Page 96

SER

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UIDE

— 95

Number of Risers: The number of Risers includes both the first and
the last Riser of the stairway.

Riser Overage or Underage: The Riser Overage or Underage is
the difference between the “floor-to-floor” Rise and the total height of
all of the Risers. Many times the Riser height does not divide evenly
into the floor-to-floor Rise and a small fraction of an Inch is left over.
A positive remainder is an Overage, while a negative remainder is
an Underage.

Tread Width: The width of each Tread is measured from the front of
one Riser to the front of the next Riser. The width of each Tread
does NOT include the nosing or overhang of the Tread. The nosing
or overhang of a Tread is the rounded front of the Tread that proj-
ects beyond the face of the Riser.

Number of Treads: The number of Treads is one less than the
number of Risers.

Tread Overage or Underage: The Tread Overage or Underage is
the difference between the Run or horizontal space that a stairway
must fit into and the total width of the Treads. Similar to the Riser
Overage/Underage, many times the total width of the Treads does
not divide evenly into the Run or horizontal space for the stairway
and a small fraction of an Inch is left over. A positive remainder is an
Overage, a negative remainder is an Underage.

Stringer: Also called a Carriage, Stair Horse, or Stair Jack. A Stringer
is the diagonal member that supports the Treads and Risers.

Angle of Incline: The angle of incline of the stairway is determined
by the Rise and Run of each stair. The angle of incline should not be
confused with the Pitch of the stairway. The Pitch of a stairway is the
angle based on the floor-to-floor Rise and the horizontal Run of the
stairway. The angle of incline is based on the “actual” Riser height
and the “actual” Tread width of the stair.

Stairwell Opening: The length of the opening at the top of the
stairs. The computation is based on the Headroom Height (the
desired spacing between the stairs and upper floor ceiling) and
thickness of the upper floor where the opening is located.