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Section 4 Finishing
plants and then assembled on the job. Even so,
the assembly work must be performed by a
skillful carpenter who understands the basic
principles of stair design and knows layout and
construction procedures.
Main stairways are usually not built or
installed until after interior wall surfaces are
complete and fi nish fl ooring or underlayment
has been laid. Basement stairs should not be
installed until the concrete fl oor has been
placed.
Carpenters build temporary stairs from
framing lumber to provide access until the
permanent stairs are installed. These are often
designed as a detachable unit so they can be
moved from one project to another. Some-
times, permanent carriages are installed during
the rough framing and temporary treads are
attached. Carriages, or stringers, are the inclined
supports that carry the treads and risers. In this
case, after the interior is fi nished, the temporary
treads are replaced with fi nished parts.
18.1 Types of Stairs
Basically, there are two stair categories:
service stairs and main stairs. Either of these
may be closed, open, or a combination of open
and closed. See Figure 18-2. In addition, the
type of stairs may be straight run, platform, or
winding.
Carriage: A sloping member that supports the risers
and treads of stairs. Also called a stringer.
Open
Closed
Combination
open and closed
Figure 18-2. Open and closed stairways. A stair is
called open even if one side is enclosed by a wall.
Figure 18-1. An attractive main stairs is a desirable
architectural feature in a residence. Stair design and
construction has long been considered one of the
highest forms of joinery.