# stair tread max length



## Hyrax4978 (Apr 7, 2019)

Is there a max length or ratio of length that might limit how long someone make a tread. 
I heard there is a code that limits only having one or two risers as a tripping hazzard but i can't find that in the code. 
the goal is to make longer treads so the stair run is not as steep. also on the exterior would like to have two steps on each tread. 

Thank you!


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## cda (Apr 7, 2019)

Rhythm??


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## cda (Apr 7, 2019)

https://inspectapedia.com/Stairs/Stair_Calculations.php


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## RLGA (Apr 7, 2019)

There is no limitation on depth of tread except for the 11-inch minimum, but it must be consistent within a flight of stairs with no more than 3/8” difference. If the tread depth is 48” or more, then it might be considered a series of landings with a single step between them if they are in a straight run. 

The problem is not the code, but potential liability from tripping.


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## fatboy (Apr 7, 2019)

Yup, just the minimum 11".


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## Msradell (Apr 7, 2019)

Hyrax4978 said:


> also on the exterior would like to have two steps on each tread.
> 
> Thank you!


I don't understand what you mean by 2 steps on each tread? Do you mean to footsteps on each tread with each 1 being something like 3+ feet long?


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## steveray (Apr 8, 2019)

Although if you make it long enough t o be a landing you would get a break on some of the other "stair stuff"...


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## RLGA (Apr 8, 2019)

steveray said:


> Although if you make it long enough t o be a landing you would get a break on some of the other "stair stuff"...


But not on handrails--one step is still a stairway by definition and requires a handrail, except for stairs in dwelling units and sleeping units of Groups R-2 and R-3.


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## Paul Sweet (Apr 8, 2019)

The old rules-of-thumb were:
2R + T = 24" to 25"
R x T = 72" to 77"
where R = riser height and T = tread width.

These extrapolate to 6" R & 12" T, 5" R & 15" T, and 4" R & 18" T.

As CDA pointed out, walking rhythm is important.  There is a stepped walk on our capitol grounds with treads that are somewhere in the 4 or 5 ft. range.  They're too long for one step and uncomfortably short for two baby steps per riser.  The least uncomfortable way to take them was to alternate one and two steps per riser, but it took a few steps to set up the pattern.


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## steveray (Apr 8, 2019)

RLGA said:


> But not on handrails--one step is still a stairway by definition and requires a handrail, except for stairs in dwelling units and sleeping units of Groups R-2 and R-3.



Or outdoors in CT...

(Amd) 1011.11 Handrails. Stairways shall have handrails on each side and shall comply with
Section 1012. Where glass is used to provide the handrail, the handrail shall also comply with
Section 2407.
Exceptions:
1. Stairways within dwelling units, Group R-1 bed and breakfast establishments and spiral
stairways are permitted to have a handrail on one side only.
2. Decks, patios and walkways that have a single change in elevation where the landing
depth on each side of the change in elevation is greater than what is required for a landing
do not require handrails.


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## Bryant (Apr 8, 2019)

don't know if it is concrete or wood, but suffice to say if using wood, you can only cut so much out and still maintain the loading on this lumber, basically notched and a 2x12!
the trick for lazy stairs and many steps is small riser. The code use to have a minimum of 4' and maxed out 7 3/4 or 8 1/4, depending on your jurisdiction. evidently that is not in the current code for the minimum.  tread depth is 9 inches plus the profile maxed out 1/ 1/4. a lot of stair stepping & treads when you go for the lazy stairs. Could go the other way a make them Billy goat grade  VRC R311.7.5.2


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## rogerpa (Apr 8, 2019)

1003.5 Elevation change. Where changes in elevation of less
than 12 inches (305 mm) exist in the means of egress, sloped
surfaces shall be used. Where the slope is greater than one
unit vertical in 20 units horizontal (5-percent slope), ramps
complying with Section 1010 shall be used. Where the difference
in elevation is 6 inches (152 mm) or less, the ramp shall
be equipped with either handrails or floor finish materials
that contrast with adjacent floor finish materials.
Exception 2.
2. A stair with a single riser or with two risers and a
tread is permitted at locations not required to be
accessible by Chapter 11, provided that the risers
and treads comply with Section 1009.7, the minimum
depth of the tread is 13 inches (330 mm) and at
least one handrail complying with Section 1012 is
provided within 30 inches (762 mm) of the centerline
of the normal path of egress travel on the stair.




Paul Sweet said:


> The old rules-of-thumb were:
> 2R + T = 24" to 25"
> R x T = 72" to 77"
> where R = riser height and T = tread width.


These rules are well over 100 years old (maybe even 150 years) and still work great today
even though we are generally taller and have larger feet.. 

1009.7.2 Riser height and tread depth. Stair riser heights
shall be 7 inches (178 mm) maximum and* 4 inches (102
mm) minimum.* The riser height shall be measured vertically
between the nosings of adjacent treads. Rectangular
tread depths shall be 11 inches (279 mm) minimum measured
horizontally between the vertical planes of the foremost
projection of adjacent treads and at a right angle to
the tread’s nosing. Winder treads shall have a minimum
tread depth of 11 inches (279 mm) between the vertical
planes of the foremost projection of adjacent treads at the
intersections with the walkline and a minimum tread depth
of 10 inches (254 mm) within the clear width of the stair.


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## mtlogcabin (Apr 8, 2019)

I remember a SBCCI instructor would tell us 2 risers plus 1 tread should not exceed 25 inches. Don't know where it came from but it works with the IBC 7/11 and the IRC 7.75/10


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## Builder Bob (Apr 8, 2019)

mtlogcabin- From the verbage in the SBCCi Code ---

Treads and Risers of stairs shall be so proportioned that the sum of two risers and a tread (minus the nosing) is not less than 24 inches nor more than 25 inches. 

1991 SBCCI section 1108.3 Treads and Risers - paraphrased.


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## mtlogcabin (Apr 8, 2019)

Builder Bob said:


> mtlogcabin- From the verbage in the SBCCi Code ---
> 
> Treads and Risers of stairs shall be so proportioned that the sum of two risers and a tread (minus the nosing) is not less than 24 inches nor more than 25 inches.
> 
> 1991 SBCCI section 1108.3 Treads and Risers - paraphrased.



Thanks.  I am surprised when an old legacy code pops into my feeble memory and then I am really glad to find out it wasn't just in my mind.


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## ADAguy (Apr 9, 2019)

Interesting historical note but no longer applicable?


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## tmurray (Apr 9, 2019)

There is a set of stairs like this at the forestry institute here. They are the most annoying things to walk up or down in the world. I walk around them to the normal set on the other side of them.


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## Builder Bob (Apr 9, 2019)

Still applicable --- IFC maintenance of MOE


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## ADAguy (Apr 9, 2019)

HMMMM ?


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## Builder Bob (Apr 15, 2019)

Fire codes require you to maintain the means of egress as originally designed..... thus the 2R+1T = 24 or 25 inches is still applicable in existing buildings.


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## manifold (May 1, 2019)

rogerpa said:


> 1003.5 Elevation change. Where changes in elevation of less
> than 12 inches (305 mm) exist in the means of egress, sloped
> surfaces shall be used. Where the slope is greater than one
> unit vertical in 20 units horizontal (5-percent slope), ramps
> ...



If the change of elevation is less than 6" and a sloped walk is used instead of a ramp, would handrails or contrasting floor finish be required?


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## steveray (May 2, 2019)

manifold said:


> If the change of elevation is less than 6" and a sloped walk is used instead of a ramp, would handrails or contrasting floor finish be required?



Nope....not a ramp until it is....Bad language though...


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## Rick18071 (May 2, 2019)

1012.8 Handrails. Ramps with a rise greater than 6 inches
(152 mm) shall have handrails on both sides. Handrails shall
comply with Section 1014.


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## ADAguy (May 2, 2019)

Yes, and back in the day the magic number was 18 for a combination of rise & run. 6/12, 7/11, etc.


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## steveray (May 2, 2019)

manifold said:


> a sloped walk is used instead of a ramp



if it is 1:21.....and 1000ft long, no HR...


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## linnrg (May 2, 2019)

Quite often I have calls from people who have had accidents on stairs.  They want the codes so that they can seek damages.  Very sad when it is the elderly.  The rhythm is a very important issue.  The uniformity, the proper handrails, the correct dimensions can not be stressed enough.


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