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This document provides building code specifications for stair treads: sketches, photographs, and examples of defects used in inspecting the step design on indoor or outdoor stairs and their treads, including the requirements for a projecting stair tread nose and the tread nose shape and dimensions..

We also include references to key documents on building codes and stair and railing safety. © Copyright 2009 Daniel Friedman, All Rights Reserved. Information Accuracy & Bias Pledge is at below-left. Use links 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.

Stair Tread Specifications & Defects

The stair treads shown in our photo are very dangerous not only because they are pitched and loose, but because there is danger of stairway collapse. The stair inspector should be asking: "What caused this weird movement and who made these goofy repairs?" Stair Step Treads Step tread depth (=> 10") (measured 12" from smaller side of irregular stair shapes such as triangular treads on curves or spirals) Step tread depth uniformity (<= 3/8" variation) Stair tread depth for winder stairs (>= 6" at smallest point) Stair tread uniformity for winder stairs at the 12" walk-line (<= 3/8" variation) Stair tread slope (out of level on walking surface) - (slope or "rise" must be <= 1 in 48) -- Source: IRC

Another Stair Code Example - Source BOCA 2001.

• Stair riser heights shall be 7 inches (178 mm) maximum and 4 inches (102 mm) minimum.
• Stair tread depths shall be 11 inches (279 mm) minimum. The riser height shall be measured vertically between the leading edges of adjacent treads. The stair tread depth shall be measured horizontally between the vertical planes of the foremost projection of adjacent treads and at right angle to the tread's leading edge.

Stair Step Tread Nose

• Tread nose projection past vertical riser below (3/4" to 1 1/2") required on stairs with solid risers (exceptions are below)
• Tread nose projection uniformity (<= 3/8" variation)
• Tread nose curve radius (=< 9/16")
• Tread Nose not required if tread depth is => 11"
• Tread Nose not required on open stair treads (open riser

Another Stair Code Example - BOCA 2001.

• Stair tread nose projection missing or wrong dimension: (falling hazard on descending) or tread nose extends out too far over tread (risk splitting off or trip on climbing up). Example: A nosing not less than 0.75 inch (19.1 mm) but not more than 1.25 inches (32 mm) shall be provided on stairways with solid risers where the tread depth is less than 11 inches (279 mm). - BOCA 2001.

Examples of stair tread defects

More Stair Tread Defects

Tread Detains on Stairs that are Curved or Angled, & Winder Stairs

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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.

STAIRS, RAILINGS, LANDINGS, RAMPS
  Attic stairs
  Balusters & Railing Enclosures
  Basement Stairs & Walkout Covers
  Books on Stair Construction
  Checklist for Stair Inspections
  Codes for Stairs
  Exterior stairs
  Fire Stopping for Stairways
  Guardrails on Balconies & Landings
  Lighting over Stairs
  Railings on Stairways
  Ramps, access
  Stair dimensions: width height &c
  Stairway headroom
  Stairway landings
  Step riser dimensions
  Step stringer defects
  Step tread dimensions
  Stair tread nose dimensions
  Winder stairs.

• 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.
• ...

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