What goes up and down but never moves?

STAIRS

Objectives

• Students will…– Identify and define the pieces within a basic set of

stairs

– Calculate the proper dimensions and layout for the rise and run of a standard stringer, given a total rise.

Total Rise – The total height from one finished floor to the other finished floor

Total Run – The total length of the stairs

Risers – The vertical member of the stairs

Treads – The step

Stringers – The structure of the stairs, usually 2 or 3 2x12’s

Nosing – The extra lip on the tread

Landing – The beginning or end of each stairs, sometimes in the middle of a flight of stairs

Balusters or Spindles – Vertical pieces under the handrail, to prevent falling off of stairs, no more than 4” apart

Handrail – To help in assisting someone up or down the stairs

Kicker – A 2x4 let into the bottom of the stringers to prevent the stairs from “kicking” out

Hanger – Usually ¾” plywood attached to the top section of the stringers to mount the stairs to the floor above

Skirt board – Decorative trim board that goes along either side, usually, of a closed stairway

Newel post – Supports the handrail, can be decorative, found at the base of the stairs

Steps To Figure Rise And # Of Stairs

• Calculating riser height video – 3 minutes

• For all stair layouts you must know:– # of risers and height, # of treads and depth

• Knowing the rise and run are the most crucial item in determining risers and treads.

• NEVER go off of a set of blueprints when determining risers and treads

Steps To Figure Rise And # Of Stairs• From your rise and run of your stairway opening, you will be able to determine 4

things: – # of risers, riser height, # of treads, and tread width

• Divide total rise (in inches) by 7 ½”

• Round answer UP to nearest WHOLE NUMBER – THIS IS THE # OF RISERS

• Divide total rise by # of risers – THIS IS THE RISER HEIGHT

• # of risers MINUS ONE = (# of treads)

• Divide run by NUMBER OF TREADS

• *** IF YOUR RISER HEIGHT OR TREAD DEPTH DO NOT FALL INTO THE ACCEPTABLE RANGE YOU MUST INCREASE OR DECREASE THE NUMBER OF RISERS!**

Turn a Decimal into a Fraction

• Multiply the decimal amount only by 16 (to get sixteenths of an inch)

• The new whole number is the new numerator (top half of the fraction)

Stair Guidelines• 2 Risers + 1Tread ~ 25 (1 riser + 1 tread ~ 17)

• Treads should be about 10” TO 12” wide

• Risers should be about 6 ½” TO 8” high

• Minimum headroom from stairs to any point above should be 6’-8”

• Nosing should not exceed 1 ½”

• Minimum stair width is 36” (stairwell opening to be 39”)

Stair Guidelines• The preferred angle of a stairway should be between 30 and

35 degrees

• When laying out the first riser THICKNESS OF THE TREAD should be deducted from the bottom

• If plywood is used as the hanger how much should be taken off of the top of the stringer? NONE, YOU MAY HAVE TO ADD THE THICKNESS OF THE RISER

• While only two stringers are required, 3 stringers are considered best practice. Stringers are usually made from 2X12– ALTHOUGH ENGINEERED LUMBER IS MORE STABLE AND STRONGER

Stair Guidelines• A FRAMING SQUARE is used to establish the height of the

HANDRAIL

• Handrails should be CLOSED in accordance with building and fire codes.

• Handrails help people up and down the stairs

• Spindles help prevent FALL-THROUGH and must be no further than 4 inches apart.

• When attaching the treads and risers using CONSTRUCTION ADHESIVE and SCREWS is the best practice.

Stair Layout

• Stair Layout – 24 minutes

• Circular Saw Safety – 25 min

• Saw blades – 7:30 minutes