Balusters and Safe Spacing for Stair Railings & Balcony or Landing Rails
Having investigated cases of severe injury related to falls and railing collapses we developed this field data collection checklist. We also include references to key documents on building codes and stair and railing safety.
Injuries due to stair or guardrail baluster failures do occur, it's not just theory. In 2006 a Tampa Bay Florida child, Julia Grimes, was critically injured after a glue-and-staple-constructed guardrail at the top of a residential stair gave way.
This accident could have been prevented if the home's owners had understood the implication of loose, wobbly balusters and guardrailing, but news reports of the guardrail failure also suggest that the railing in a home built in 1994 and constructed using glue and staples, was unable to withstand anticipated loads (200 pounds) or even smaller forces such as that imposed by a child leaning on the railing. - Tampa Bay Times, 18 January 2006 cited at REFERENCES
Even if the guardrailing has adequate strength it may be unsafe if it is too low or if the spacing between its balusters is too great. Horizontal guardrail enclosures are also a child hazard.
We often see guards and railings enclosed using horizontal members or mesh or link fencing materials. Because a toddler can easily climb these materials, they are not safe for guard or railing enclosures and should not be used.
We also often see decks and porches more than 30" above ground level with no guardrail whatsoever, perhaps relying on the placement of plants or furniture to discourage people from stepping too close to the edge.
Where building code enforcement was absent or lax we found a deck eight feet above ground with no railings at all. A local inspector opined that because the deck was not attached to the house (it abutted the house) it was exempt from building code enforcement.
Our opinion was that code exemption did not do much to reduce the falling hazard and that guards and railings should be provided regardless.
Look closely at stair and guard rail balusters for loose, split, broken, or damaged balusters. Someone tried an over-sized common nail to "repair" this loose baluster at its connection to the stair tread.
The result is a dangerous child hazard as this baluster could easily be pushed out of place.
Balusters for Guards & Railings
Stairway handrail & stair balusters & guard details are in this sketch.
Balusters (vertical posts comprising the barrier in guards and railings)
Baluster opening between vertical members (maximum sphere passage <= 4 3/8" or in U.S. and some other jurisdictions <= 4") [Thanks to Steve Stanczyk for pointing out that 4 inches is the maximum recommended baluster space opening width]
Baluster opening in triangular area below stair guard bottom rail and stair tread (maximum sphere passage <= 6")
Hand-railing heights are given:
U.S. handrails for stairs with one side against a wall: 30-38"
U.S. handrails at open stairs: 34-38" above the stairs
Canadian stair handrails: 32-36" above the stairs
Wall clearance: Handrails along a wall must have at least 1.5" of clearance between the inside surface of the rail and the wall surface.
Railings should not project into the required width of the stairway by more than 4.5" at or below the handrail height above the stairs.
Floor clearance: OPINION: we recommend either 4" between bottom surface of the guardrail or stair rail bottom and the top of the floor surface, or use 2" or less to avoid a foot trap. See the foot trap anecdote we report at GUARDRAILS on BALCONIES, DECKS, LANDINGS
Reader Question: Methods for reducing the space between stair balusters that are too far apart
We have an apartment complex in Oregon, and the insurance company is requiring that we tighten up the metal posts on the railings.
The railings on the premises currently have vertical balusters that are more than 4 inches apart. Baluster spacing of 4 inches increase the protection for small children sliding through. It is recommended to replaced the railing with vertical balusters that are no more than 4 inches apart to reduce the risk of small children falling. Is there an easy fix for this? - Tami 7/23/12
Reply: Suggestions for tightening up baluster spacing at a stair railing:
We made this same repair recently on a circular stair that had vertical balusters that were too far apart by having our welder add additional balusters in between the existing ones so that the opening was less than 4" between baluster pairs. This was less costly than tearing out the whole rail and building a new one to exactly 4" on spec. Our new balusters varied a bit but were about 3.5" apart side to side or on center.
Watch out though: if you make the vertical balusters too close together, but far enough apart for a toddler to stick a foot through the space - say 2 1/2" they can become a foot trap. No child will fall through but s/he an get a foot stuck in the space by inserting it between the balusters, then turning it to one side.
The ensuing panic requires an adult to sort out and remove the foot - as happened with my Godson Joshua Waterman years ago. His mom called me in hysterics that his foot was stuck in the balusters at their home and he couldn't get it out. I drove like a madman across town but just as I arrived in the driveway Josh turned his foot the proper direction and extracted himself from the trap without any adult assistance.
Use the "Click to Show or Hide FAQs" link just above to see recently-posted questions, comments, replies, try the search box just below, or if you prefer, post a question or comment in the Comments box below and we will respond promptly.
Nguyen, Dong-Phong, "Girl falls 15 feet when stair spindles snap", Tampa Bay Times, 18 January 2006, original source: http://www.sptimes.com/2006/01/18/Hillsborough/Girl_falls_15_feet_wh.shtml, Excerpt: Julia leaned against the banister and the wooden spindles suddenly snapped, causing her to fall 15 feet to the ceramic floor below, according to police.
The spindles inside the $1.2-million home, police later reported, had been held together with glue and staples.
Julia was flown to Tampa General Hospital where she remained in critical condition Tuesday, said hospital spokeswoman Ellen Fiss.
 Thanks to Mark Cramer, Tampa Florida, for assistance in technical review of the "Critical Defects"
section and for the photograph of the deteriorating gray Owens Corning flex duct in a hot attic. Mr. Cramer is a Florida home inspector and
home inspection educator.
 Thanks to Steve Stanczyk, a professional home inspectcor, (Safe Haven Inspections, Kapowsin Washington 98344) for pointing out that the maximum spacing between stair or guardrail balusters should be limited to 4 inches. Mr. Stanczyk can be reached also by email at email@example.com
Eric Galow, Galow Homes, Lagrangeville, NY. Mr. Galow can be reached by email: firstname.lastname@example.org or by telephone: 914-474-6613. Mr. Galow specializes in residential construction including both new homes and repairs, renovations, and additions.
 "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
 Access Ramp building codes:
 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
 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. "
 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
 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 email@example.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. [copy on file as http://www.stairways.org/pdf/2006%20Stair%20IRC%20SCREEN.pdf ] -
 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.
 "The Dimensions of Stairs", J. M. Fitch et al., Scientific American, October 1974.
 Stair & Walkway Standards for Slipperiness or Coefficient of Friction (COF) or Static Coefficient of Friction (SCOF)
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)
 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
 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)
 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
 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
 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.
 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
 "Coefficients of Friction for Ice", The Physics Factbook™, Glenn Elert, Ed., retrieved 8/29/12, original source: http://hypertextbook.com/facts/2004/GennaAbleman.shtml
 "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.
 Serway Physics for Scientists and Engineers 4th edition (p. 126.)
 "How Slippery Is It", retrieved 8/29/12, original source http://www.icebike.org/Articles/howslippery.htm
 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.
 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 ]
 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
 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]
 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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