1. Stairs

2. Objectives Be able to calculate size needed for a staircase
Apply staircase calculation to own stairs
Identify types of staircase designs
Gain knowledge of general size information

3. Stairway
Series of steps with or without landings or platforms which is installed between two or more floors of a building
Provides easy access to various levels
All styles of homes have stairs except ________?
Ranch Design

4. Main stairs vs. service stairs
Generally prefabricated parts and are of a much better quality than the service stairs
Typically made from hardwoods (oak, maple, birch)
Service stairs
Typically constructed on site of Douglas fir or pine (construction lumber)

5. Seven types of stairs Straight run L stairs Double-L stairs U stairs
Winder stairs
Spiral stairs
(Circular stairs)

6. Straight run stairs No turns
Not as expensive as other types to construct
Require a longer open space

7. L stairs One landing at some point along the flight of steps “long L”
Used when there is not enough space for straight run

8. Double L stairs Two 90 degree turns along the flight
Typically not used in residential construction
Expensive and break up the floor plan

9. U stairs Wide or narrow U Two flights of steps parallel to each other
Landing between the two flights of steps

10. Winder stairs Pie shaped steps
Width of the triangular/pie shaped steps?
Sufficient at midpoint
Not as safe as other stairs

11. Spiral stairs Gaining in popularity
Used where little space is available
Most are made from steel and welded together
Not very safe

12. Circular stairs Custom made Trapezoid shaped steps
Large homes. Probably too big for your two-story houses

13. Terminology Open Stairs-stairs that have no wall on one or both sides
Enclosed stairs-have a wall
on both sides
(“housed” or “box” stairs)

14. Terminology
Landing-floor area at either end of stairs and possibly in between

15. Terminology Rail (handrail)-
Designed to be grasped by the hand. They are supported by posts or fixed directly to a wall.
Baluster-
Vertical member that supports
the handrail.

16. Terminology
Newel-main posts of the handrail at the top, bottom or points in between where stairs change directions

17. Handrail
Newel

18. Terminology
Stringer (string’ er)- structural member that supports the treads and risers
Two are usually sufficient. But if width exceeds 3 feet, a third stringer is needed
Plain stinger
Housed/closed stringer

19. Plain Stringers Made from fir
Risers and treads nailed directly to the stringer
Service stairs, main stairs if they are carpeted
Sturdy
Squeaky and do not have a finished appearance
Risers are 1in and treads are typically 2in

20. Housed Stringers Made from finished lumber
Generally precut or preassembled
Stringer is routed to hold the treads and risers
Wedges are driven in to hold in place
Glued and nailed in place

21. Terminology
Nosing-rounded projection of the tread that extends past the riser

22. Terminology
Tread- horizontal member of each step. Usually 1 ¼” thick. Either 10½”(most popular) or 11½” deep
Run-the distance from the face of one riser to the face of the next
Total Run-total horizontal length of the stairs
10-1/2”
10-1/2”

23. Terminology
Riser-vertical face of a step. Usually ¾” thick, between 7” and 7 5/8” high
Rise-distance from the top of one tread to the same position on the next tread
Total Rise-total floor-to-floor height
7” – 7 5/8”
7” – 7 5/8”
7” – 7 5/8”

24. Terminology
Headroom-shortest clear vertical distance between the nosing on the treads and the ceiling (6’-8” minimum)
6’-8” min.

25. Rules Stairs should be minimum 3’-0” wide (traffic circulation rule)
The slope of the stairs (rise-run ratio) should be between 30 and 35 deg
The sum of two risers and one tread should equal approximately 25 in
The product of the riser height multiplied by the tread width should equal appox. 75in
The sum of one riser and one tread should be inches

26. Procedures What is your Ceiling Height of your first floor?
Example Problem:
What is your Ceiling Height of your first floor?
(Standard ceiling height: 8’ - 12’) _________
Add together: finished floor to finished ceiling (Ceiling Ht.) ________ thickness of ceiling material (drywall) .5” width of floor joists (2” x 10”) 9.5” thickness of subfloor (.5” plywood) .5” thickness of finished floor ”
Total Rise = ________
10’-0”
Ceiling Height
10’-0”
10’-11 ¼ ”

27. Procedures Convert Total Rise from feet to inches.
[ _________ x 12 ] + _________ = __________
Divide Total Rise (inches) by 7” (min. riser height) to find the total number of risers for your stairs.
_________ = __________ 10
11 ¼
131.25”
# of feet
leftover inches
Total Rise (inches)
131.25”
18.75
Total Rise (inches)
# of Risers

28. Procedures
If your Total Riser # is a decimal, plug the whole number into the equation below, WITHOUT the decimal part:
Example: If the Total Riser # is 22.18, plug in 22
_________ _________ = __________
The numbers below would allow you to draw elevations
How many Risers do your stairs have? ________
What is the Height of Each Riser? ________
131.25” 18
7.29”
Total Rise inches
# of Risers
(w/out decimal)
Height of Each Riser (inches) 18
7.29”

29. Procedures Calculate Total Run
_________ x [_________ - 1] = __________
Convert Total Rise and Total Run back into Inches.
_________ = __________ (For Elevations)
_________ = __________ (For Floor Plans)
10.5” 18
178.5”
Tread Depth
# of Risers
Total Run
***THERE IS ALWAYS ONE LESS TREAD THAN RISER
131.25”
approx. 10’-11”
Total Rise (in)
Total Rise (ft/in)
approx. 14’-10”
178.5”
Total Run (in)
Total Run (ft/in)

30. Neat-looking Stairs

31. Neat-looking Stairs

32. Neat-looking Stairs

33. Neat-looking Stairs

34. Neat-looking Stairs

35. Neat-looking Stairs