Masonry stair trip hazard at Justin Morrill Smith historic home Strafford Vermont (C) Daniel Friedman Exterior Stairway & Walkway Trip & Fall Hazard
Stair defect photos

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Outdoor or exterior building stair and step & walkway trip and fall hazards are described and illustrated with photographs of bad designs, inadequate maintenance, or other hazards that can lead to trip and fall injuries outdoors on and around buildings.

We discuss dilapidated stair structures: rot, loose connections, pitched, wobbly, missing parts, collapse risk. unsafe landscape-tie or railroad tie step and walk tripping hazards. slip trip fall defects in masonry steps and landings outdoors.slippery exterior stair surfaces: glass & tile.curved, tall, or uneven stair fall hazards. clandestine trip and fall hazards at low decks & platforms. algae, ice, fungus, & other stair slip, trip & fall hazards.

We illustrate common trip points and we describe good practices for safe stairs and walks outdoors. We include a discussion of the role of stair railings or handrails and stair fall injuries, and we also discuss the role of wood species, wood treatment, and maintenance in exterior stair fall injuries.

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Guide to Common Exterior Stair Slip Trip & Fall Hazards

Dilapidated wood stairs, Portland Maine area (C) Daniel FriedmanDilapidated Stair Structures: rot, loose connections, pitched, wobbly, missing parts, collapse risk

This article focuses on slip trip and fall hazards on exterior stairs, landings, platforms, decks, balconies & their railings. 5

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.

[Click to enlarge any image]

Our page top photo of a scary stair to nowhere was photographed by the author (DF) in Majorca in 2002. At left we document a collapsing wood stairway observed in Maine.

And some stair design requirements, such as stair treads that will not hold water, naturally pertain principally to outdoor stairways.

Unsafe Landscape-tie or railroad tie step and walk tripping hazards

Landscape tie stair trip hazard (C) Daniel Friedman

Here 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.

It's common for gravel, dirt, or asphalt to settle inside of the step perimeter made of landscape ties such as shown in our photo.

When the wood projection is 1/8" or more above the other walking surface (asphalt in this photo) it's a tripping hazard that should be corrected.

Landscape tie stair edges raised above brick or stone interior - trip hazard (photo at left)

These steps are also wet, adding a naturally-occurring slip, trip, and fall risk that may combine with or even be mistaken for the actual cause of a fall here - catching the toe of one's shoe on the raised landscape tie during passage down these steps.

Landscape tie stair rot and insect damage (C) Daniel Friedman Landscape tie stair rot and insect damage (C) Daniel Friedman

Slip Trip Fall Defects in Masonry Steps and Landings Outdoors

Masonry stairs have of course been constructed and used for quite a while, even pre-dating modern building code and safety associations and legal remedy should the stair user fall.

At the Pyramid of the Sun outside of Mexico City (DF 2011) the stairs to the pyramid top are very tall and very steep and with a high rise. They are easier to ascend (below left), than to descend (below right - the author is in the blue shirt).

Masonry stair at the Pyramid of the Sun, Mexico City (C) Daniel Friedman Masonry stair at the Sun Pyramid, Mexico (C) Daniel Friedman

Masonry stair treads should be slightly pitched away from the riser in order to drain water away from the riser side of the step - you don't need much pitch to drain, 1" in 45" of run is sufficient and won't violate building code.

Loose brick exterior stairs (C) D Friedman

Good drainage on a masonry stair (or walk) also reduces damage from frost-related surface spalling and cracking.

Masonry stairs should be protected from frost heaves by proper gravel, backfill, drainage, and other construction details.

Our brick steps photograph (above left) illustrates loose bricks at the nose of an exterior stair - a likely trip and fall hazard. Low stairs such as these may be excluded from local building code requirements for a handrail, but nevertheless they can form a serious tripping hazard.

At below left we illustrate solid stone masonry stairs that are frost-damaged, pitched (photo, Justin Morrill Smith Historic Site, Strafford VT). These stone steps are more than 100 years old and have been left "as is" for historic reasons. They are a tripping hazard. And even properly sized solid stone stairs can become a trip hazard after 100 to 150 years of foot traffic such as the stairs shown at below right. These steps are in the Hacienda Jaral de Berrio and date from the 1700s.

Masonry stair trip hazard at Justin Morrill Smith historic home Strafford Vermont (C) Daniel Friedman Masonry stair trip hazard at Justin Morrill Smith historic home Strafford Vermont (C) Daniel Friedman

Slippery Exterior Stair Surfaces: glass & tile

Masonry stair trip hazard using glass - slippery when wet (C) Daniel Friedman

Exterior stairs are slippery when coated with algae (discussed below), wet leaves, iced or snow: that's obvious.

But other sources of slippery exterior stairs include use of particular materials that become particularly slippery when wet.

At above left we illustrate a more subtle stairfall hazard in these otherwise creative stairs designed by a Guanajuato artist. The use of glass bottles at the stair tread nose provides a surface that will be quite slippery when wet.

Curved, Tall, or Uneven Stair Fall Hazards

Slippery glass and tile included in exterior stairs in Mexico (C) Daniel Friedman

Stair steps that are curved like these steps we photographed in Tucson Arizona can be tricky to use and in our OPINION are a trip and fall hazard

Stair Landings onto a Sloped Surface May be Fall Hazards

Exterior stair with sloped landing (C) Daniel Friedman

Stair steps that terminate at a sloped surface where there is not room for a level platform present a complex of problems.

At above left is an exterior stair that I [DF] was in the process of constructing along with Art Cady. The treads were level and well supported with deep cleats; the railings are incomplete.

But the termination of the steps on a slope required not only custom-cut stringers and special measures for stair support, it also gave us a stair landing problem.

The bottom landing is at a narrow driveway that slopes. Had we included an appropriate stair landing platform, passage along the narrow drive became a problem for vehicles.

The stair had other issues - notice the incomplete and discontinuous hand railings.

A technically-correct solution for these stairs may have been an intermediate platform and a turn of the stairs to the right, continuing descent through a cut-away portion of the hill, ending on a level platform that in turn stepped onto the sloping drive. Still the user ends by stepping off of a level platform onto a slope.

Slippery glass and tile included in exterior stairs in Mexico (C) Daniel Friedman

Stair steps that have a high and/or uneven rise like these steps we photographed (also in Tucson) violate building stair code standards for uniformity (more than1/4" difference in step rise) are a trip and fall hazard.

This building entry also lacks an entry platform and the steps lack a handrail.

Clandestine Trip and Fall Hazards at Low Decks & Platforms

Slippery glass and tile included in exterior stairs in Mexico (C) Daniel Friedman

Stair steps at the edge of a low entry platform, deck or patio like the step shown at left may comply with the letter of building codes in may areas - there are only two steps and the total height of the platform is less than 36" above ground.

But we see the following trip and fall hazards at this location

Examples of Causes of Exterior Stair Collapse & Fall Injury Hazards

Collapsed exterior wooden stairs (C) Daniel Friedman

Causes of Collapses at Wooden Exterior Stair Steps & Rails

Because a stairway collapse can occur suddenly and without warning to the stair users, injuries on these steps can be particularly egregious. Our photographs illustrate and we list below many of the common causes of collapsing exterior wooden stairs. Contact us to suggest additions to this material.

Over deep cuts into the stair stringer risk collapse (C) Daniel Friedman

While we like the idea of supporting the treads on top of a notch into the stair stringer (in some regards it's potentially a stronger support than using stair tread brackets or cleats) the very deep notches cut into the 2x stair stringer in our photo left about three inches of wood to carry the weight of the stairs.

In sum, instead of a 2x12 carrying the weight of the stairs, the stair support has been reduced to a 2x4.

Of course there are quite a few other troubling conditions at the stairs in our photo.

Collapsing exterior stairs with no tread support (C) Daniel Friedman

In our photograph, the stone stair treads are a nice material, but at just stacking stone treads on a vertical clay block has created the following hazards:

Failure to connect stairs to structure (C) Daniel Friedman

Stairs are usually connected to the building at the top or head of the stair stringers using structural connectors, perhaps in combination with a ledger board between the interior surfaces of the stringers. If the stairs ascend a building side wall, the stair stringer on that side is also often connected to the building wall for added support and stiffness.

What's holding the steps in place (photo at left) is that concrete apron at lower right in our photo. Take a closer look (click to see an enlarged image of any photo or sketch in our articles) and you can see that the stair stringer has just a corner in contact with the building and the step treads slope down towards the sidewalk.

Add the absence of a hand railing, uneven step rise, possible algae on the step surface, a curved bottom stair tread of different height, and we've got multiple conditions asking for a stair slip trip and fall accident at this Hudson New York building.

Stair treads set on cleats (C) Daniel Friedman

In our photo the stair treads are supported on 2x4 cleats nailed to the stair stringer. It looks like two 12d common galvanized nails were used.

Is this enough? Click to enlarge the photo and notice that the cleats on the outer stringers must have been through-bolted to the stringer (see the bolt heads) - a more secure connection.

Too many nails can be as bad as too few in wood frame construction, as excessive nailing splinters and destroys the wood connection.

End nailing of stair treads through the stringer is an inadequate support for the tread and is exceptionally dangerous (as the author has experienced).

Watch out: When an end-nailed stair tread breaks away from the stringer (the tread surface splits or the stringers separate from the treads), the tread falls away leaving a sharp nail end extending into the walking area exactly where it can rip open a walker's ankle or leg in the course of the stair fall.

Repair attempt for wobbly exterior stairs (C) Daniel Friedman

Algae, Ice, Fungus, Wet Surfaces Can Cause slips and falls on stairs

Algae growth on steps or decks: green or sometimes black algae grows readily on wood, concrete, or stone surfaces in most climates, particularly where those surfaces are repeatedly wet and especially if the surface is also shaded. Algae makes these walking surfaces dangerously slippery when wet - a slip, trip and fall hazard which is widely recognized. [29][30][31][32]

Aglae slip hazard on wood steps (C) Daniel Friedman Stair support unsafe (C) Daniel Friedman

The steps at left and deck at right were inspected by the author who in fact nearly had a bad fall due to wet algae on the deck where the ladder was placed. You can see the scrape marks of the ladder feet (where my pen is pointing in the photo, above right) and the good luck that the ladder slippage was stopped by the chimney base.

It is readily observed that algae growth on wood surfaces may seem harmless when the steps are dry, but when any stair surface, stone, brick, wood, or other, is covered with algae and becomes wet, the surface is extremely slippery, adding significantly to the risk of a serious fall and injury.

Snow & Ice on Exterior Ramps, Stairs, or Walks is a Serious Fall & Injury Hazard

Snow covered exterior stair (C) Daniel FriedmanFailure to keep exterior walking surfaces free of ice and snow is discussed extensively in literature on fall hazards in climates where freezing conditions occur.

Some particularly helpful research citations on snow and ice slip trip and fall hazards are given just below.

Snow and ice may cause or contribute to very serious falls and falls that may be witnessed by more people - as the walker is outdoors - than indoor slips, trips and falls that may occur where the field of view for second-party observers is more limited.

See SNOW & ICE REMOVAL on WALKS & STAIRS where we discuss approaches to making these walking surfaces more safe.


Continue reading at SLIPPERY STAIRS, WALKS where we discuss the coefficient of friction on various walking surfaces under various conditions as well as anti-slip stair and walk or ramp construction recommendations from building codes and standards.

Or see SLIP TRIP & FALL HAZARD LIST, STAIRS for our complete guide to causes of stair & walk slips and falls.

Or see HANDRAILS & HANDRAILINGS for handrailing and stair railing specifications and hazards that can be a major contributor to stair fall injuries.


Suggested citation for this web page

SLIPS, TRIPS & FALLS, EXTERIOR STAIRS at - online encyclopedia of building & environmental inspection, testing, diagnosis, repair, & problem prevention advice.


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