Exterior Stairways: Guide to Outdoor Stair, Railing, Landing Construction Codes & Hazard Inspection

EXTERIOR STAIRS - home. Exterior or Outdoor Stair, railing, guardrail, landing, tread, and step specifications & codes
- Construction Requirements for Safe Outdoor Steps, Stairs, Railings, Newell Posts - exterior stair trip & fall hazards
- Outdoor Stair & railing safety hazards, photos of defects; Defects in Masonry Steps and Landings Outdoors
- Sketches of exterior stair design requirements
DECK STAIR BUILDING START- separate article
DECK STAIR BUILDING DETAILS - separate article
EXTERIOR STAIR FALL HAZARDS - separate article
Questions & Answers about Exterior Stair Code Specifications & Construction
References

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Exterior stairway construction details & suggestions for safe stairways: this document provides building photographs, and examples of defects found in inspecting indoor or outdoor stairs, railings, landings, treads, and related conditions for safety and proper construction. We include references to articles cataloging the causes of stair slips, trips, and falls and to building code specification details for proper stair, landing, balcony and railing construction.

Exterior Stair Code Specifications & Construction Recommendations

A stair inspection checklist provided in this document outlines information to collect during a field investigation of the condition of an interior or exterior stairway for safety defects. Having investigated cases of severe injury related to falls and railing collapses we developed this field data collection checklist

See Catalog of Stair Trip Fall Hazards and Exterior Stair Falls, where we catalog just about every cause of exterior stair slip trip and fall hazards;
Also see Stairway landings and Deck & Porch Steps or Stairs.
For building construction code specification details for steps, stairs, & railings, see Codes for Stairs

While in general the building code specifications for exterior stairs, landings, and railings are the same as for indoor star is, we often see special trip hazards at exterior stairs and walks, conditions that do not occur indoors, and details which may escape some building inspectors.

When we encounter steps and a deck such as the version shown in our photo (above left) we are confident that the construction was done without the benefit of building permits and code approvals, is unsafe, and may harbor other hidden structural or safety hazards.

And some stair design requirements, such as stair treads that will not hold water, naturally pertain principally to outdoor stairways. We add some more subtle warnings about outdoor stairs and stair construction, and tips or tricks of carpentry and masonry to avoid problems with stairs.

Construction Requirements for Safe Outdoor Steps, Stairs, Railings, Newell Posts

Stair support unsafe (C) Daniel Friedman

Proper structural support for the stair assembly is critical to avoid catastrophic failures and serious injuries. Our two stair photos just above show a large, complex exterior stair built along a rocky hillside - more of a cliff. The lack of connection of supporting posts to piers below this stair was appalling.
Proper exterior stair tread drainage: Outdoor stairs should be designed so as not to accumulate water on the tread surface Wet stair tread surfaces become slippery from water, ice, or algae and fungal growth.

Watch out: as we detail at Exterior Stair Falls, algae, ice, snow and water make outdoor stairs very slippery and dangerous.

Figure 1-31: Cupping of flat sawn lumber (C) Wiley and Sons, S Bliss

Wooden stair treads should be installed with the end grain curve "down" vs "up": which way?

Notice the end-grain of boards to be used as stair treads, and make sure that when building a wooden outdoor stair tread you place the tread boards with the "bark side" down - the wood grain visible at the end of stair tread boards should arc down.

The image shown at left, courtesy S. Bliss, Best Practices in Residential Construction, depicts the end grain of wooden deck boards stair treads as they would appear if you had placed the bark side down. The bark side of lumber determines the natural curvature of the tread board as the wood dries, and it makes for the best stair tread drainage and the minimum cupping or or holding of water on the stair tread. But which way is right: bark side up or bark side down.
We don't agree with this sketch as shown here and would have flipped these boards (or stair treads over). In our experience, while there are certainly exceptions, left alone most often boards arch up or out towards the bark side as they dry.

We like bark side up. Details about this construction safety tip are at BARK SIDE UP on DECKS & STEPS. There we include this additional warning:

Watch out: On wooden decks and stair treads a defect shelling can occur with the bark side down method. Shelling is a term used by some builders to refer to the loss of portions of a board surface as late wood growth (the outer surface of the tree and thus the "bark side" of the board) separates from early wood growth (the inner portion of the tree or the tree-center side of the board).
If after construction a deck or stair tread board misbehaves and cures with a concave cup that will tend to hold water (and form algae, ice and slip hazards such as discussed at Slippery Stairs, Walks), drill small drainage holes in the center of the cupped board. Make sure the drain holes won't catch a high-heeled shoe by making them small or locating them out of the walking path.

Exterior Stairs - Incomplete, Unsafe, Missing Guardrails

Unsafe fire exit stairway (C) Daniel Friedman

This exterior stair appears to have been installed as a fire-exit way, but lacks a guardrail around the stair top balcony.

It is exactly during an emergency that a frightened user is more likely to fall at this location.

...

Frequently Asked Questions (FAQs) About Exterior Stair & Railing construction, inspection, safety, repair

Question: safety & design questions for sloped, pitched, & narrow exterior masonry steps

My mother is elderly and is moving from her home to a co-op building. Her unit is on the first floor and her patio is served by an outdoor staircase made of flagstone steps. There is a steep incline to the steps, and they seem to be too narrow for the incline. We have asked the board of the co-op if we can widen each step from their current width of 23 1/2 inches to 30 inches.

Sloped narrow exterior stairs (C) InspectAPedia & P.O.

The board is opposing our request to widen the steps on aesthetic grounds, and not considering my mother's safety.

They are allowing us to rebuild the staircase, as it was poorly built to begin with.

Is there a way to determine what the proper width of each flagstone should be (side to side) based on the incline of the staircase? What I would like to do if possible is to show the board from a mathematical standpoint what the proper width of the steps (from side to side) should be in relation to the steepness of the incline.

If I can't appeal to them on ethical or moral grounds, maybe I can convince them that it's the proper thing to do based on the incline to create a safe staircase for my mother.

I have attached some photos below for reference, however they really don't show how steep the steps actually are when you try to climb them especially when they're wet or icy or have snow on them.

A wider step from side to side would definitely make one feel more confident negotiating the steps up and down.

I appreciate any technical input or knowledge you can provide that would help me with my request to the board.

Thank you. P.O. 11/10/2012

Reply:

P.O.

From your photos, two of which we include above, I see a trip hazard where someone routes a garden hose across a stair tread - the hose can easily wind up in the walking path and is a serious trip hazard for anyone, young or elderly.

Recommended stairway width for an exterior stair

In a companion article STAIR DIMENSIONS, WIDTH, HEIGHT you can read standard stair measurements. There you'll find that the stairs you describe are more narrow in width than recommended.

You will want to involve the local building code officials in the jurisdiction where your mom's stairs are located. But we point out that in general, the minimum recommended stair width is between 34" and 36" Across the width of the tread.

Private stairways shall be a minimum of thirty-six inches wide. Trim and handrails may not encroach into this
minimum width by more than 3 1/2 inches. The maximum rise of each step is eight inches; the minimum rise
is four inches. The minimum run is nine inches. The largest tread width or riser height in any flight of stairs
shall not exceed the smallest by more than 3/8 inch. - stair codes vary; this quote is from he CBC 1003.3.3 Stairways and Landings model code

The stairs you describe are a less than the minimum recommended width, and in my OPINION we should do all feasible to make stairs safe and navigable particularly where their users are known to include people at extra risk of falling injuries.

Recommended pitch for drainage on exterior stairs

In a second companion article STEP TREAD DIMENSIONS you will see that although it makes perfect sense to provide a slight slope to exterior stair treads so that they will drain, the slope must be very slight, not more than 1 inch of rise in 48" of run. The "incline" of the stairway - a consideration in your original question - does not determine the recommended stairway width. But indeed if the steps are too pitched (say for aggressive drainage) that excessive pitch is itself a trip and fall hazard.

Stair tread slope (out of level on walking surface) - (slope or "rise" must be <= 1 in 48) -- Source: IRC

Other things to check for exterior stair & walkway safety

Is the riser height uniform and in the recommended height range - (<= 7.75" high and with no variation > 3/8") ?
The minimum recommended stair landing length is 36" (or a length and width sufficiently greater than the swing of the door if a wider door is present. So the ending of the stairs (not shown in your photos) may also need improvement.
Even if the total rise of the stairs is small enough (3 ft. or less total change in elevation from ground level at first step to topmost step height in many jurisdictions), I'd recommend a handrailing. My own mother, also elderly, has tripped on a dead flat surface, and easily falls on even a single step.
Check that the exterior stair walking surfaces are level when measured side-to-side - in your photos the stairs look to as if they might be out of level in two directions.

Also see

EXTERIOR STAIR FALL HAZARDS for a catalog of common slip trip and fall hazards on exterior stairs and check out
SLIP TRIP & FALL HAZARD LIST, STAIRS as well as
SLIPPERY STAIRS, WALKS

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Technical Reviewers & References

Related Topics, found near the top of this page suggest articles closely related to this one.

Carson, Dunlop & Associates Ltd., 120 Carlton Street Suite 407, Toronto ON M5A 4K2. (416) 964-9415 1-800-268-7070 info@carsondunlop.com. The firm provides professional home inspection services & home inspection education & publications. Alan Carson is a past president of ASHI, the American Society of Home Inspectors. Thanks to Alan Carson and Bob Dunlop, for permission for InspectAPedia to use text excerpts from The Home Reference Book & illustrations from The Illustrated Home. Carson Dunlop Associates' provides:
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Best Practices Guide to Residential Construction, by Steven Bliss. John Wiley & Sons, 2006. ISBN-10: 0471648361, ISBN-13: 978-0471648369, Hardcover: 320 pages, available from Amazon.com and also Wiley.com. See our book review of this publication.
Eric Galow, Galow Homes, Lagrangeville, NY. Mr. Galow can be reached by email: ericgalow@gmail.com or by telephone: 914-474-6613. Mr. Galow specializes in residential construction including both new homes and repairs, renovations, and additions.
[3] "The Elimination of Unsafe Guardrails, a Progress Report," Elliott O. Stephenson, Building Standards, March-April 1993
[4] "Are Functional Handrails Within Our Grasp" Jake Pauls, Building Standards, January-February 1991
[5] Access Ramp building codes:
- UBC 1003.3.4.3
- BOCA 1016.3
- ADA 4.8.2
- IBC 1010.2
[6] Access Ramp Standards:
- ADA (Americans with Disabilities Act), Public Law 101-336. 7/26/90 is very often cited by other sources for good design of stairs and ramps etc. even where disabled individuals are not the design target.
- ANSI A117.4 Accessible and Usable buildings and Facilities (earlier version was incorporated into the ADA)
- ASTM F 1637, Standard Practice for Safe Walking Surfaces, (Similar to the above standard
[7] The Circular Staircase, Mary Roberts Rinehart
[8] Construction Drawings and Details, Rosemary Kilmer
[9] Falls and Related Injuries: Slips, Trips, Missteps, and Their Consequences, Lawyers & Judges Publishing, (June 2002), ISBN-10: 0913875430 ISBN-13: 978-0913875438
"Falls in the home and public places are the second leading cause of unintentional injury deaths in the United States, but are overlooked in most literature. This book is unique in that it is entirely devoted to falls. Of use to primary care physicians, nurses, insurance adjusters, architects, writers of building codes, attorneys, or anyone who cares for the elderly, this book will tell you how, why, and when people will likely fall, what most likely will be injured, and how such injuries come about. "
[10] Mobile Home Inspections common defects unique to factory built housing, inspection methods
[11] The National Institute of Standards and Technology, NIST (nee National Bureau of Standards NBS) is a US government agency - see www.nist.gov
- "A Parametric Study of Wall Moisture Contents Using a Revised Variable Indoor Relative Humidity Version of the "Moist" Transient Heat and Moisture Transfer Model [copy on file as/interiors/MOIST_Model_NIST_b95074.pdf ] - ", George Tsongas, Doug Burch, Carolyn Roos, Malcom Cunningham; this paper describes software and the prediction of wall moisture contents. - PDF Document from NIS
[12] 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)
[13] Slips, Trips, Missteps and Their Consequences, Gary M. Bakken, H. Harvey Cohen, Jon R. Abele, Alvin S. Hyde, Cindy A. LaRue, Lawyers and Judges Publishing; ISBN-10: 1933264012 ISBN-13: 978-1933264011
[14] The Stairway Manufacturers' Association, (877) 500-5759, provides a pictorial guide to the stair and railing portion of the International Residential Code. [copy on file as http://www.stairways.org/pdf/2006%20Stair%20IRC%20SCREEN.pdf ] -
[15] How to Clean Moldy Wood Framing & Sheathing How to clean/seal mold from/on exposed lumber or plywood subfloor or roof sheathing indoors - some suggestions based on our field and laboratory research
[16] Mold-Resistant Building Practices, advice from an expert on how to prevent mold after a building flood and how to prevent mold growth in buildings by selection of building materials and by anti-mold construction details.
[17] Steps and Stairways, Cleo Baldon & Ib Melchior, Rizzoli, 1989.
[18] The Staircase, Ann Rinaldi
[19] Common Sense Stairbuilding and Handrailing, Fred T. Hodgson
[20] The Art of Staircases, Pilar Chueca
[21] Building Stairs, by pros for pros, Andy Engel
[22] A Simplified Guide to Custom Stairbuilding, George R. Christina
[23] Basic Stairbuilding, Scott Schuttner
[24] The Staircase (two volumes), John Templar, Cambridge: the MIT Press, 1992
[25] The Staircase: History and Theories, John Templar, MIT Press 1995
[26] Steps and Stairways, Cleo Baldon & Ib Melchior, Rizzoli, 1989.
[27] "The Dimensions of Stairs", J. M. Fitch et al., Scientific American, October 1974.
[28] Stair & Walkway Standards for Slipperiness or Coefficient of Friction (COF) or Static Coefficient of Friction (SCOF)
- ANSI A1264.2
- ANSI B101
- ASTM D-21, and ASTM D2047
- UL-410 (similar to ASTM D-21)
- NSFI 101-B (National Floor Safety Institute)
- NSFI Walkway Auditing Guideline (WAG) Ref. 101-A& 101-B (may appear as ANSI B101.0) sets rules for measuring walkway slip resist
- OSHA - (Dept of Labor CFR 1910.22 does not specify COF and pertains to workplaces) but recognizes the need for a "qualified person" to evaluate walkway slipperiness
- ADA (relies on the ANSI and ASTM standards)
[29] A. Sacher, International Symposium on Slip Resistance: The Interface of Man, Footwear, and Walking Surfaces, Journal of Testing and Evaluation (JTE), ISSN: 1945-7553, January 1997 [more focused on slipperiness of polished surfaces
[30] Algae is widely recognized as a slippery surface - a Google web search for "how slippery is algae on steps" produced more than 15,000 results on 8/29/12)
[31] Slipperiness of algae on walking surfaces, warning, Royal Horticultural Society, retrieved 8/29/2012, original source: http://apps.rhs.org.uk/advicesearch/profile.aspx?pid=418
[32] Slipperiness of algae: "Watch your step, wet rocks and algae are slippery" Oregon State University warning 1977 retrieved 8/29/2012, original source: http://www.worldcat.org/title/watch-your-step-wet-rocks-and-algae-are-slippery/oclc/663683915
[33] Coefficient of friction of algae on surfaces [like stair treads]: Delphine Gourdon, Qi Lin, Emin Oroudjev, Helen Hansma, Yuval Golan, Shoshana Arad, and Jacob Israelachvili, "Adhesion and Stable Low Friction Provided by a Subnanometer-Thick Monolayer of a Natural Polysaccharide", Langmuir, 2008 pp 1534-1540, American Chemical Society, retrieved 8/29/2012,
Abstract: Using a surface forces apparatus, we have investigated the adhesive and lubrication forces of mica surfaces separated by a molecularly thin, subnanometer film of a high-molecular-weight (2.3 MDa) anionic polysaccharide from the algae Porphyridium sp. adsorbed from aqueous solution. The adhesion and friction forces of the confined biopolymer were monitored as a function of time, shearing distance, and driving velocity under a large range of compressive loads (pressures). Although the thickness of the dilute polysaccharide was <1 nm, the friction was low (coefficient of friction = 0.015), and no wear was ever observed even at a pressure of 110 atm over 3 decades of velocity, so long as the shearing distances were less than twice the contact diameter. Atomic force microscopy in solution shows that the biopolymer is able to adsorb to the mica surface but remains mobile and easily dragged upon shearing. The adhesion (adsorption) of this polysaccharide even to negatively charged surfaces, its stable low friction, its robustness (high-load carrying capacity and good wear protection), and the weak (logarithmic) dependence of the friction force on the sliding velocity make this class of polyelectrolytes excellent candidates for use in water-based lubricant fluids and as potential additives to synovial fluid in joints and other biolubricating fluids. The physical reasons for the remarkable tribological properties of the ultrathin polysaccharide monolayer are discussed and appear to be quite different from those of other polyelectrolytes and proteins that act as thick “polymer brush” layers.
[34] Jinjin Li, Yuhong Liu, Jianbin Luo, Pengxiao Liu, and Chenhui Zhang, "Excellent Lubricating Behavior of Brasenia schreberi Mucilage" Langmuir 2012 28 (20), 7797-7802
[35] Jason R. Stokes, Lubica Macakova, Agnieszka Chojnicka-Paszun, Cornelis G. de Kruif, and Harmen H. J. de Jongh, "Lubrication, Adsorption, and Rheology of Aqueous Polysaccharide Solutions, Langmuir 2011 27 (7), 3474-3484
[36] "Coefficients of Friction for Ice", The Physics Factbook™, Glenn Elert, Ed., retrieved 8/29/12, original source: http://hypertextbook.com/facts/2004/GennaAbleman.shtml
[37] "Coefficients of Friction for Ice", The University of the State of New York Reference Tables for Physical Setting/Physics. New York: The State Education Department, 2002. Op. Cit.
[38] Serway Physics for Scientists and Engineers 4th edition (p. 126.)
[39] "How Slippery Is It", retrieved 8/29/12, original source http://www.icebike.org/Articles/howslippery.htm
[40] John E. Hunter, "Friction Values", The Source, Society of Accident Reconstructionists, Winter 1998. Study of frictional values of car tires involved in collisions on snow or ice covered roadways.
[41] Frictional Coefficients of some Common Materials and Materials Combinations, The Engineering Toolbox, retrieved 8/29/2012, original source: http://www.engineeringtoolbox.com/friction-coefficients-d_778.html [copy on file as Friction and Coefficients of Friction.pdf ]
[42] Stairways and Ladders, A Guide to OSHA Rules, OSHA, U.S. Department of Labor, 3124-12R 2003 - Web Search 05/28/2010 original source: http://www.osha.gov/Publications/osha3124.pdf. OSHA regulations govern standards in the construction industry and in the workforce Quoting from OSHA whose focus is on workplace safety and so excludes discussion of falls and stair-falls in private homes:

OSHA estimates that there are 24,882 injuries and as many as 36 fatalities per year due to falls from stairways and ladders used in construction. Nearly half of these injuries are serious enough to require time off the job--11,570 lost workday injuries and 13,312 non-lost workday injuries occur annually due to falls from stairways and ladders used in construction. These data demonstrate that work on and around ladders and stairways is hazardous. More importantly, they show that compliance with OSHA's requirements for the safe use of ladders and stairways could have prevented many of these injuries. -osha.gov/doc/outreachtraining/htmlfiles/stairlad.html
[43] International Building Code, Stairway Provisions, Section 1009: Stairways and Handrails, retrieved 8/29/12, original source: http://www.amezz.com/ibc-stairs-code.htm [copy on file as IBC Stairs Code.pdf]
[44] Model Building Code, Chapter 10, Means of Egress, retrieved 8/29/12, original source: http://www2.iccsafe.org/states/newjersey/NJ_Building/PDFs/NJ_Bldg_Chapter10.pdf, [copy on file as NJ_Bldg_Chapter10.pdf] adopted, for example by New Jersey. International Code Council, 500 New Jersey Avenue, NW, 6th Floor, Washington, DC 20001, Tel: 800-786-4452

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The Home Reference Book - the Encyclopedia of Homes, Carson Dunlop & Associates, Toronto, Ontario, 25th Ed., 2012, is a bound volume of more than 450 illustrated pages that assist home inspectors and home owners in the inspection and detection of problems on buildings. The text is intended as a reference guide to help building owners operate and maintain their home effectively. Field inspection worksheets are included at the back of the volume. Special Offer: For a 10% discount on any number of copies of the Home Reference Book purchased as a single order. Enter INSPECTAHRB in the order payment page "Promo/Redemption" space. InspectAPedia.com editor Daniel Friedman is a contributing author.

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Best Practices Guide to Residential Construction, by Steven Bliss. John Wiley & Sons, 2006. ISBN-10: 0471648361, ISBN-13: 978-0471648369, Hardcover: 320 pages, available from Amazon.com and also Wiley.com. See our book review of this publication.
Decks and Porches, the JLC Guide to, Best Practices for Outdoor Spaces, Steve Bliss (Editor), The Journal of Light Construction, Williston VT, 2010 ISBN 10: 1-928580-42-4, ISBN 13: 978-1-928580-42-3, available from Amazon.com
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