The basic structure of the stair depends primarily on whether the stairway is to be located inside or outside and whether it is to be protected from the weather or not. The wood-stair details discussed in this chapter can be employed for either interior or exterior stairways, although the location will suggest basic detailing differences due to the fact that one is protected from the weather and the other isn’t.
Interior stairs—Interior stairs are usually more refined than exterior stairs. Interior stairways may be the showcase of a building and so are often located near the entry and used as a major circulation route. They may also provide the opportunity to connect more than one floor with natural light.
Exterior stairs—Exterior stairs (see 222) have the same minimum proportional requirements as interior stairs, but they are generally built less steep. The treads need to be deeper and risers shallower outdoors to make the stairs safer when wet or covered with snow or ice. Materials on exterior stairs must also be chosen with the weather in mind. Weather-resistant materials such as concrete, masonry, and metal are sound choices for stairs exposed to the elements. Heavy timber or pressure-treated wood is often chosen for a wood stair out of doors. Special attention should be paid to nonskid surfaces for treads exposed to the weather.
Some exterior stairs are supported directly on the ground, in which case they are usually called steps (see 223-225). Ground-supported steps follow the contours of sloping sites to provide easy access to porches or entrances or as connections between terraces and other landscape elements.
