STAIR A stairway is a series of steps with or without landings that is installed between two or more floors of a building. A building may have a main stair, which is usually assembled with quality prefabricated materials and/or a service stair, which is assembled with common building materials.

Stair Types • Straight Run Stair

Used mostly in residential construction, inexpensive to build but requires a long open space in the floor &/or ceiling to accommodate design

• L-Stair

Has one landing at some point along the stairway and is used when space for a straight run stair is not available

• Double L-Stair

An L-Stair that requires two landings along the stairway and is not typically used in residential construction

• Winder Stair An L-Stair with “pie-shaped” steps in place of the landing and is used when space is not sufficient for the L-Stair

• U-Stair

Two separate but parallel stairways connected by a landing in-between

• Spiral Stair

A series of “pie-shaped” steps coiled around a center post, used where little space is available and as a result are not as efficient as other stairs

Stair Terminology • Enclosed Stair

A stair with a wall on both sides • Open Stair

A stair without a wall on one or both sides • Stringer

A structural member that supports the treads and risers

• Plain Stringer

A stringer that has been cut to fit the profile of the stairs

• Housed Stringer

A stringer that has been grooved to receive the treads and risers

• Tread The horizontal member of a step

• Riser

The vertical member of a step • Nosing

The rounded projection of the tread

• Rise The distances from the top of one tread to the top of the next

• Run

The distance from the face of one riser to the face of the next

• Rough Opening

The opening in the floor or ceiling that allows travel up and down a stairway

• Landing

The floor area at either end of the stair and possibly at some point in-between

• Headroom

The shortest clear vertical distance measured from the nosing of a tread to the ceiling

• Total Rise

The total floor-to-floor vertical height • Total Run

The total horizontal length of the stair

• Newel The main posts of the handrail

• Balusters

The vertical members that support the handrail on open stairs

• Handrail

The railing attached to a wall next to a stairway and is used to help people steady themselves as they travel along the stairway

• Guardrails

The single rail installed at a specified height above a landing to keep people from going over the edge of a balcony

1. Determine the total rise of the stairway.

2. Determine the number of risers by dividing the total rise by 7. The reason 7 is used is because it is an ideal riser height. The number of risers must be an exact number so continue to divide your total rise by different measurements (7-1/8, 7-1/4, 7-3/8, etc…) until you achieve this. Each riser must be exactly the same height.

Procedures for Stair Calculations/Drawing The following procedure may be used to determine the number and size of treads and risers for a set of stairs

3. Determine the tread size/depth and total run that will yield a stair slope/angle between 30 and 35 degrees. An ideal tread measures 10-1/2”. There is always one less tread than the number of risers

1. The sum of 2 risers and 1 tread equals 25”

2. The product of the riser height multiplied by the tread width should equal approx. 75”

3. The sum of 1 riser and 1 tread should equal 17” – 18”

4. Locate stairwell rough opening, which is determined by the headroom dimension (minimum of 6’-6”)

Works Cited

Kicklighter, Clois E., Ronald J. Baird, and Joan C. Kicklighter. Architecture: Residential Drawing and Design. South Holland, IL: Goodheart-Willcox, 1995. Print.