2. STAIRS AND STAIR FRAMING

3. Lesson Objectives Describe what stair construction is.
Define terms associated with stair construction.
Calculate the unit rise, unit run, angle of incline, and number of treads for a stairway given the total run and rise.

4. STAIRS
STAIR – a series of steps, each elevated a measured distance, leading from one level of a structure to another.
“Flight of Stairs” – a continuous series of steps without breaks formed by landings or other constructions

5. STAIRS
Types of Stairs
Main Stairs
Straight Run, Platform, and Winding
Service Stairs
Stairways are usually not built or installed until after interior wall surfaces are complete and finish flooring has been laid.

6. Stair Terminology
Stairwell – the rough opening in the floor above to provide headroom for stairs
Stringer – one of the inclined sides of a stair that supports the risers and treads
Riser – the vertical surface between two treads
Tread – the horizontal face of one step

7. Stair Terminology
Nosing – the part of the tread that extends over the riser beneath it
Newel – the post that supports the railing
Handrail – an angled piece supported by a wall or railing intended to be grasped by persons
Balusters – vertical members supporting the handrail on open stairs

8. Stair Terminology
Platform – a horizontal area placed between to flights of stairs
Landing – the floor at the top or bottom of each story where a flight of stairs begins or ends
Winders – Wedge-shaped treads installed where stairs turn
Unit Run – the width of a tread minus the nosing

9. Stair Terminology
Unit Rise – the height or a riser; vertical distance between two treads
Total Run – the sum of all unit runs
Total Rise – the sum of all unit rises
Headroom – the vertical distance from a step to a ceiling above

10. Rough Opening
The rough opening for the stairwell must be carefully laid out and constructed
Trimmers and headers should be doubled for support

11. Designing Stairs Stair Angle should fall between 30 and 35 degrees
The sum of two risers and one tread should be 24 to 25”
The sum of one riser and on tread should equal 17 to 18”
An 11” run and a 7” rise follows all three rules.
The stair width should be a 3’ minimum with a 3’2” – 3’4” preferred width
Headroom for a main stairwell should be a minimum of 6’8”

12. How many steps do I need?
What is the total rise from 1st floor to second floor? _______
What is the rise of each step? ________”
Calculate the steps needed:
Total Rise from 1st to 2nd floor = # Steps
Rise of each Step