Stairstep height: Guide to Stair Riser Dimensions in Stair Codes, Construction & Stair Inspections InspectAPedia® -
Stair step riser height specifications & codes
Stair & railing inspection form
Stair & railing safety hazards, photos of defects
Sketches of stair design requirements
Our site offers impartial, unbiased advice without conflicts of interest.
We will block advertisements which we discover or readers inform us are associated with bad business practices,
false-advertising, or junk science. Our contact info is at
InspectAPedia.com/appointment.htm.
This document provides building code specifications, sketches, photographs, and examples of the proper step height or stair riser dimensions and other stair riser requirements for indoor or outdoor stairways. Sketch courtesy Carson Dunlop.
Step riser slope (out of vertical) (<= 30 deg measured from horizontal surface of the tread)
Step risers: open risers are permitted provided the opening will not pass a 4" sphere (child safety)
Stair Riser Defects
Stair risers of uneven height - no variation greater than 0.375 inches is allowed
Stair risers of improper height, too tall
Stair risers of improper height, too short
Bad Deck Stair Example: Nothing is right about the exterior stairs shown in our photo from a 1991 home inspection:
This stair stringer is too-deeply notched and could split;
The stair risers are too high, as our client is showing with our tape.
The stair treads are too narrow.
There is no railing and the height above ground is more than 36".
The deck and platform railing is open with no balusters.
Stairway Measurements, Dimensions & Rules
Because more people are injured by trips and falls than other hazards, experts have looked closely at the specifications for stairs, steps, and rails to reduce the falling hazards.
This work has been translated into stair and railing specifications that are similar among codes and countries (but not identical). -- IBC, IRC, BOCA, Kingston NY Stair Code, & other sources. Sketch courtesy Carson Dunlop.
Rules for Constructing Stairs that are Curved or Angled, & Winder Stairs
Angled or Curved stair treads are a particular trip hazard, especially because of the lack of uniformity and because the tread width at the inside of the curve can be too small for safe walking.
Our stair photo at above left shows tricky angled stairs that were squeezed onto a sidewalk in New York City. A passerby agreed to model the risk of falling. Sketch courtesy Carson Dunlop.
My daughter fell down curved stairs at a shopping mall where the triangular tread hazard was combined with a beautiful, architect-designed handrail that was about 8" in diameter - she was unable to grasp it as she was falling.
The photo shows her sister grasping n added handrail that was welded on to correct this unsafe condition.
The original "fat" hand railing that no one could grasp when falling is along the diagonal-right side of the photo.
Critique, contributions wanted: Contact Us to suggest corrections or additions to articles at this website, and if you wish, to receive online listing and credit as a contributor. Particular thanks are due to the many experts and also consumers who read and critique technical articles at InspectAPedia.com.
Additional technical contributors & reference sources for this article are listed below.
Use links just below or at the left of each page to navigate this document or to view other topics at this website. Green links show where you are in our document or website.
Thanks to Alan Carson and Bob Dunlop, Carson Dunlop, Associates, Toronto, for permission to use illustrations from their publication, The Illustrated Home which illustrates construction details and building components. Carson Dunlop provides home inspection education, publications, report writing materials, and home inspection services. Alan Carson is a past president of ASHI, the American Society of Home Inspectors.
Books & Articles on Building & Environmental Inspection, Testing, Diagnosis, & Repair
Our recommended books about building design, inspection, and repair, and about indoor environment testing, diagnosis, and cleanup are at the InspectAPedia Bookstore.
"The Elimination of Unsafe Guardrails, a Progress Report," Elliott O. Stephenson, Building Standards, March-April 1993
"Are Functional Handrails Within Our Grasp" Jake Pauls, Building Standards, January-February 1991
Slips, Trips, Missteps and Their Consequences, Second Edition, Gary M. Bakken, H. Harvey Cohen,A. S. Hyde, Jon R. Abele, ISBN-13: 978-1-933264-01-1 or
ISBN 10: 1-933264-01-2,
available from the publisher, Lawyers ^ Judges Publishing Company,Inc., www.lawyersandjudges.com sales@lawyersandjudges.com and also from the InspectAPedia Bookstore (Amazon.com)
The Stairway Manufacturers' Association, (877) 500-5759, provides a pictorial guide to the stair and railing portion of the International Residential Code.
The following stair books and other books on stair history, design, and architecture can be purchased at our Amazon-Supported InspectAPedia Bookstore
Steps and Stairways, Cleo Baldon & Ib Melchior, Rizzoli, 1989.
The Staircase: History and Theories, John Templar, MIT Press 1995
The Staircase (two volumes), John Templar, Cambridge: the MIT Press, 1992.
"The Dimensions of Stairs", J. M. Fitch et al., Scientific American, October 1974.
More Information on Building Diagnostic Inspections and Repairs
...
InspectAPedia® Home & Site Map - Building & Environmental Inspection, Testing, Diagnosis, Repair, & Problem Prevention Advice: In-depth research & advice on diagnosing, testing, correcting, & preventing building defects & indoor environmental hazards. Unbiased information, no conflicts of interest.
The Mold Information Center: What to Do About Mold in Buildings, When and How to Inspect for Mold, Clean Up Mold, or Avoid Mold Problems
Environmental Inspection, Testing, & Diagnosis On-Site IAQ, Gas, Air Testing, Mold Investigation, Sick Building Diagnosis, Lab Services, & Remediation Plan Preparation - indoor air quality testing, problem source determination, supporting lab work, written remediation plan addressing removal of environmental and other hazards and prevention of their recurrence.
InspectAPedia ® Home & Site Map 
InspectAPedia® Home & Site Map
