Installation Guide

Tread Overhang
Minimum = 3/4”
Maximum = 1-1/4”
Exceptions:
An overhang is not
required where treads
are a minimum of 11
inches deep.
A nosing not less than 3/4 inch but not more than 1-1/4 inches shall be
provided on stairways with solid risers (See Fig. 1). The greatest nosing
projection shall not exceed the smallest nosing projection by more than 3/8
inch between two stories, including the nosing at the level of floors and
landings (See Fig. 3). The maximum riser height shall be 7-3/4 inches. The
riser shall be measured vertically between leading edges of the adjacent
treads (See Fig. 2). The greatest riser height within any flight of stairs shall not
exceed the smallest be more than 3/8 inch (See Fig. 4). The minimum tread
depth shall be 10 inches. The tread depth shall be measured horizontally
between the vertical planes of the foremost projection of adjacent tread’s
leading edge. The greatest tread depth within any flight of stairs shall not
exceed the smallest by more than 3/8 inch (See Fig. 5).
Tread Overhang
Nosing projection may
not vary more than 3/8”
Minimum Depth 10”
Maximum Riser
Height 7-3/4”
Tread
Overhang
7-3/4”
7-5/8”
10”
10-1/8”
10-3/8”
7-3/8”
Greatest Rise 7-3/4”
Smallest Rise - 7-3/8”
3/8”
Examplse stair is within
acceptable code limits
Greatest Tread Depth 10-3/8”
Smallest Tread Depth - 10”
3/8”
Examplse stair is within
acceptable code limits
FIGURE 1
STAIR BUILDING CODE
FIGURE 2 FIGURE 3
FIGURE 4 FIGURE 5