Reasons for Failure. In most cases, it takes 10 to 20 years
for the failure of a stair to occur. Failure is
most often due to exposure to rain and sun and accelerated by poor maintenance or
poor design. Failure can result in loose stair treads which can lead to
falls or water intrusion and
dry rotted wood.
Building Codes. Depending on the extent of the repair, associations may be required to
bring the stair into compliance with current code. Current code does
not allow stairs to be as steep or narrow as they once were.
Definitions. The following definitions apply to stairs.
Guardrail:
The guardrail is designed to prevent falls from stairs of decks greater
than 30 inches above the ground. Current code requires the guardrail to
be no less that 42 inches high (it was 36 inches before) and designed
to prevent a 4 inch diameter sphere from passing through it (it was 6
inches before). The current code also requires the guardrail to be
strong enough to resist a 200 pound load along the top of the rail.
Handrail:
The wood or steel tube or rod that ascends with the stairs. Handrails
are required by code on both sides of an exterior stair. There are very
few exceptions to this code requirement. They are required to be of a
specific diameter, shape and distance from the wall or guardrail. They
are required to extend past the top and bottom of the stair and to
terminate in such a manner that a shirt sleeve or bracelet will not get
caught on the handrail.
Nosing: Where the riser intersects with the tread.
Risers:
The vertical space or surface at the back of each tread which separates
one tread from the next tread. Sometimes the riser is open meaning an
object can pass through it. Sometimes the riser is closed. Closed risers
comply with current building codes, open risers do not comply. The
risers are to be consistent in height and have a current code limit of
no less than 4 inches high and no greater than 7 inches high.
Stringer:
This is the structural beam (wood or steel) that runs parallel to the
treads as they ascend. There are times when there is no visible stringer
because it is either embedded in a wall or hidden with finish
materials.
Treads:
The horizontal surface of the stairs that you step on. These can be
made of pre-cast concrete (made at a factory), steel, wood or some type
of solid (hopefully waterproof) deck coating. The treads are required to
be uniform in depth and have a minimum depth of 11 inches to meet
current code.

PRECAST CONCRETE TREADS AND RISERS
The tread and riser are formed out of one piece of pre-cast concrete.
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PRECAST CONCRETE TREADS
AND STEEL STRINGER
The concrete tread bolts to the steel angle welded to the steel
stringer. If this stair was not under a roof, we would likely see rust
where the tread attaches to the steel angle.
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PRECAST TREADS WITH WOOD STRINGERS
This stair
does not comply with current codes for tread depth, closed risers,
guardrail height or handrail design.
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WOOD STAIR WITH WATERPROOF COATING
The stair framed of wood and coated with a waterproof coating. The stringers are hidden in the stucco coated guardrail walls.
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STAIR FAILURE
Water penetrated the
stringer where the steel angle supports the pre-cast concrete tread.
Thirty years later there was little wood left to support this stair. The
red tape and plastic is the destructive testing holes created to
determine the extent of the damage.
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WOOD ROT AT STAIR
Dry rot is a
fungus which feeds on wood. Once it gets started it is difficult to stop
and will spread to the deck and living unit. The photos above show the
extensive decay of the stair stringers and guardrails. It would just be a
matter of time for the entire stair to collapse if left alone.
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NEW STAIR AND TEMPORARY STAIR
A new replacement stair is being constructed on the right. A temporary stair
which allows ingress and egress for second floor occupants during the
construction is located on the left.
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NEW AND OLD
A new stair is on the left and an old stair is on the right. The
new stair is wood framed with a waterproof coating. The stair on the
right is pre-cast concrete treads connected to stringers covered by the
stucco coated guardrails.
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Quick Tips for Managing Stairs:
- Stairs with waterproof coating should
be inspected annually to confirm the coating has not been compromised by
furniture moving or misuse. Pre-cast concrete stairs should be checked
with every painting (3 to 5 years depending on your climate) to confirm
the treads are tight and the stringers are structurally sound.
- Be diligent in maintaining the paint
where pre-cast concrete treads touch the stringer and where there
are exposed fasteners (bolts, screws, etc.).
- Replacement or repair of treads
typically does not require a building permit. With few exceptions we
have found that repair or replacement of stair stringers require
building permits.
- Prior permit experience with stair
replacement or repairs in one city does not mean that another city will
permit the stairs the same way. Although the building code is a
statewide code, the Building Official in each city is the final
interpreter of the code.
Thank you to Smith Architects for providing this information.
ASSISTANCE: Associations needing legal assistance can
contact us.
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