Chapter 18 Stair Construction
603
only one side is suffi cient. Figure 18-11 illustrates
the correct height for a rail.
A complete set of architectural plans should
include detail drawings of main stairs, especially
when the design includes any unusual features.
For example, the stair layout in Figure 18-12 shows
a split-level entrance with open-riser stairs leading
to upper and lower fl oors. An exact description of
tread mountings, overlap, nosing requirements,
and height of the handrail is not included. These
items of construction are the responsibility of
Nosing
approximately 1 1/4"
6 1/2" Rise
12" Run
Approximately 30˚
(6 1/2 + 6 1/2) + 12 = 25
7 1/4" Rise
Approximately 35˚
(7 1/4 + 7 1/4) + 10 1/2 = 25
Tread
10 1/2" Run
Riser
8" Rise
Approximately 42˚
(8 + 8) + 9 = 25
9" Run
Figure 18-8. Be careful about rise-run relationships in stair design.
Figure 18-9. This L-shaped stairs is wide enough for
moving furniture up and down. (C-E Morgan)
Wall rail
3'-0" minimum
3'-2" or 3'-4"
preferred
Figure 18-10. A main stair should be at least 3′ wide
for easy movement of people and furniture.
Wall or
handrail
36"
30"
34"
42"
Landing
Figure 18-11. A handrail height of 30″ at the rake
(slope) and 34″ at the landings has been an accepted
standard. Recently, building codes in some places
have been adopting heights of 36″ at the rake and 42″
at landings. (C-E Morgan)