Stairs
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
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
Ranch Design
 All styles of homes have stairs except ________?
Main stairs vs. service stairs
 Main 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)
Seven types of stairs
 Straight run
 L stairs
 Double-L stairs
 U stairs
 Winder stairs
 Spiral stairs
 (Circular stairs)
Straight run stairs
 No turns
 Not as expensive as other types to construct
 Require a longer open space
L stairs
 One landing at some point along the flight of steps
 “long L”
 Used when there is not enough space for straight run
Double L stairs
 Two 90 degree turns along the flight
 Typically not used in residential construction
 Expensive and break up the floor plan
U stairs
 Wide or narrow U
 Two flights of steps parallel to each other
 Landing between the two flights of steps
Winder stairs
 Pie shaped steps
 Width of the triangular/pie shaped steps?
 Sufficient at midpoint
 Not as safe as other stairs
Spiral stairs
 Gaining in popularity
 Used where little space is available
 Most are made from steel and welded together
 Not very safe
Circular stairs
 Custom made
 Trapezoid shaped steps
 Large homes. Probably too big for your two-story houses
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)
Terminology
 Landing-floor area at either end of stairs and
possibly in between
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.
Terminology
 Newel-main posts of the handrail at the top,
bottom or points in between where stairs change
directions
Handrail
Newel
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
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
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
Terminology
 Nosing-rounded projection of the tread that
extends past the riser
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”
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”
Terminology
 Headroom-shortest clear vertical distance
between the nosing on the treads and the ceiling
(6’-8” minimum)
6’-8” min.
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 17-18 inches
Procedures
Example Problem:
 What is your Ceiling Height of your first floor?
(Standard ceiling height: 8’ - 12’)
10’-0”
_________
Ceiling Height
Add together:
finished floor to finished ceiling (Ceiling Ht.)
thickness of ceiling material (drywall)
width of floor joists (2” x 10”)
thickness of subfloor (.5” plywood)
thickness of finished floor
10’-0”
________
.5”
9.5”
.5”
.75”
10’-11 ¼ ”
Total Rise = ________
Procedures
 Convert Total Rise from feet to inches.
131.25”
10
11 ¼
[ _________
x 12 ] + _________
= __________
# of feet
leftover inches
Total Rise (inches)
 Divide Total Rise (inches) by 7” (min. riser height) to find
the total number of risers for your stairs.
131.25”
18.75
_________
7 = __________
Total Rise (inches)
# of Risers
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
131.25”
_________
18
7.29”
_________
= __________
Total Rise inches
# of Risers
(w/out decimal)
Height of Each Riser (inches)
 The numbers below would allow you to draw elevations
18
How many Risers do your stairs have? ________
7.29”
What is the Height of Each Riser? ________
Procedures
 Calculate Total Run
10.5”
18
178.5”
_________
x [_________
- 1] = __________
Tread Depth
# of Risers
Total Run
***THERE IS ALWAYS ONE LESS TREAD THAN RISER
 Convert Total Rise and Total Run back into Inches.
131.25”
10’-11” (For Elevations)
_________
12 = approx.
__________
Total Rise (in)
178.5”
_________
Total Run (in)
Total Rise (ft/in)
14’-10”
12 = approx.
__________
Total Run (ft/in)
(For Floor Plans)
Neat-looking Stairs
Neat-looking Stairs
Neat-looking Stairs
Neat-looking Stairs
Neat-looking Stairs
Neat-looking Stairs