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Space between stair treads and sidewall

tbz said:
It's very simple, as noted if you have closed stringers boxing in the treads, then the space between the stringer and the outer wall / guard MUST Be LESS THAN 4" in IBC, however this is posted in the IRC, thus on the sides, a sphere 3.375 can't pass, thus not matter if it is closed in or not, the tread ends and the guard on the open side can't pass 3.375.

If it does, it fails, unless you have a local amendment.
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I was thinking the same thing. Using the same standard is certainly reflecting the INTENT of the Code
Well Done
 
mtlogcabin said:
The 4 3/8" is so a toddler cannot get his head through. That just does not work on a set of stairs/walking surface that a toddler can crawl on and get his legs or chest stuck in. Sorry all you get is 1/2 inch opening

R104.1 General.
The building official is hereby authorized and directed to enforce the provisions of this code. The building official shall have the authority to render interpretations of this code and to adopt policies and procedures in order to clarify the application of its provisions. Such interpretations, policies and procedures shall be in compliance with the intent and purpose of this code. Such policies and procedures shall not have the effect of waiving requirements specifically provided for in this code.

1011.7.1 Stairway walking surface.
The walking surface of treads and landings of a stairway shall not be sloped steeper than one unit vertical in 48 units horizontal (2-percent slope) in any direction. Stairway treads and landings shall have a solid surface. Finish floor surfaces shall be securely attached.

Exceptions:

1. Openings in stair walking surfaces shall be a size that does not permit the passage of 1/2-inch-diameter (12.7 mm) sphere. Elongated openings shall be placed so that the long dimension is perpendicular to the direction of travel.
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I'm sorry, but as an architect you are completely wrong here and I find that your interpretation of the code is so far out of what is actually practiced I feel that you are setting a very bad precedent and are communicating bad information.

I have the 2012 IBC Code and Commentary book in front of me, and it says:

Stairway and Walking surface.

It is the intent of this section that both landing and stair treads be solid and level with firmly attached surface materials; however, the 1:48 slope should be adequate to allow for drainage to limit the chance for an accumulation of water where someone might slip.

The exceptions permit the use of open grate-type material or slotted grill for stairway treads and landings in two different situations.

Exception 1 allows for a maximum 1/2-inch (12.7 mm) opening on stairway treads in public areas and serving any use (see Figure 1009.9.1). This is very beneficial on exterior stairways where snow, ice or water may accumulate. The 1/2-inch (12.7 mm) limitation is consistent with ICC A117.1 and federal accessibility requirements. The opening limitation is small enough that most shoe heels will not get stuck. If a slotted grill pattern is used, the slots must run side to side on the stairway tread, not front to back.

Exception 2 is applicable in factory, industrial, storage and high-hazard occupancies. This provision is intended to apply primarily to stairs that provide access to areas not required to be accessible, such as pits, catwalks, tanks, equipment platforms, roofs or mezzanines. Walking surfaces with limited-size openings are typically used because open grate-type material is less susceptible to accumulation of dirt, debris or moisture, as well as being more resistant to corrosion. Most...
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blah blah blah you get the point.

Anyways, as you can see, this code section is applicable only to the actual tread surface material itself, and is not referencing a gap or space between the tread material and other building elements, such as guards, walls or stringers.

The definition of walking surface = a "surface" you walk on. An open space = no surface = not a walking surface!
Nowhere in the code does it say that a stair tread must extend all the way to a solid vertical toe kick, wall, plate or stringer with either zero or a 1/2" gap.
There are plenty of examples of permitted stairs that have open ends.

This is backed up by the fact that in the book they have posted this image which clearly shows a stair with no edge or toe kick, with 3-4" spacing between the guard balustrade posts.

Then in the 1015.4 Opening Limitations, it also clearly mentions under Exception #6:

"Within individual dwelling units and sleeping units in Group R-2 and R-3 occupancies, guards on the open sides of stairs shall not have openings that allow passage of a sphere 4 3/8 (111 mm) inches in diameter.

Note it says "open sides of stairs" that shall block a 4 3/8" sphere, not 1/2". This seems very unambiguous.
 

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Penguin87 said:
I'm sorry, but as an architect you are completely wrong here and I find that your interpretation of the code is so far out of what is actually practiced I feel that you are setting a very bad precedent and are communicating bad information.

I have the 2012 IBC Code and Commentary book in front of me, and it says:


blah blah blah you get the point.

Anyways, as you can see, this code section is applicable only to the actual tread surface material itself, and is not referencing a gap or space between the tread material and other building elements, such as guards, walls or stringers.

The definition of walking surface = a "surface" you walk on. An open space = no surface = not a walking surface!
Nowhere in the code does it say that a stair tread must extend all the way to a solid vertical toe kick, wall, plate or stringer with either zero or a 1/2" gap.
There are plenty of examples of permitted stairs that have open ends.

This is backed up by the fact that in the book they have posted this image which clearly shows a stair with no edge or toe kick, with 3-4" spacing between the guard balustrade posts.

Then in the 1015.4 Opening Limitations, it also clearly mentions under Exception #6:

"Within individual dwelling units and sleeping units in Group R-2 and R-3 occupancies, guards on the open sides of stairs shall not have openings that allow passage of a sphere 4 3/8 (111 mm) inches in diameter.

Note it says "open sides of stairs" that shall block a 4 3/8" sphere, not 1/2". This seems very unambiguous.
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Welcome to the Forum with your fairly aggressive first post!...So supreme architect being of the universe, how far is the guard or wall allowed to be set back from the edge of a walking surface until it becomes "open"? The fact is, the IBC does not address this condition yet, so building officials will do what they think is right and that is what MT is doing...I think we tried to address this in 2024 (and handrail setbacks) but I can't remember how that went...
 
Yes, Welcome to the forum.
2018 IRC
[RB] GUARD. A building component or a system of building components located near the open sides of elevated walking surfaces that minimizes the possibility of a fall from the walking surface to the lower level.
R311.7.5.1 Risers.
The riser height shall be not more than 73/4 inches (196 mm). The riser shall be measured vertically between leading edges of the adjacent treads. The greatest riser height within any flight of stairs shall not exceed the smallest by more than 3/8 inch (9.5 mm). Risers shall be vertical or sloped from the underside of the nosing of the tread above at an angle not more than 30 degrees (0.51 rad) from the vertical. At open risers, openings located more than 30 inches (762 mm), as measured vertically, to the floor or grade below shall not permit the passage of a 4-inch-diameter (102 mm) sphere.

In the code there are two sections that address openings related to stairs and they both address openings that are in a vertical position. The only codes that address openings in a horizontal position (floor, stairs or landings) are limited to a maximum 1/2 inch.

2018 IBC
1011.7.1 Stairway walking surface.
The walking surface of treads and landings of a stairway shall not be sloped steeper than one unit vertical in 48 units horizontal (2-percent slope) in any direction. Stairway treads and landings shall have a solid surface. Finish floor surfaces shall be securely attached.

Exceptions:

1. Openings in stair walking surfaces shall be a size that does not permit the passage of 1/2-inch-diameter (12.7 mm) sphere. Elongated openings shall be placed so that the long dimension is perpendicular to the direction of travel.

So as an Architect in your humble opinion where does the walking surface of a tread end? 1" from the guard or 12 inches from the guard or maybe somewhere in between? What would you accept?
 
mtlogcabin said:
Yes, Welcome to the forum.
2018 IRC
[RB] GUARD. A building component or a system of building components located near the open sides of elevated walking surfaces that minimizes the possibility of a fall from the walking surface to the lower level.
R311.7.5.1 Risers.
The riser height shall be not more than 73/4 inches (196 mm). The riser shall be measured vertically between leading edges of the adjacent treads. The greatest riser height within any flight of stairs shall not exceed the smallest by more than 3/8 inch (9.5 mm). Risers shall be vertical or sloped from the underside of the nosing of the tread above at an angle not more than 30 degrees (0.51 rad) from the vertical. At open risers, openings located more than 30 inches (762 mm), as measured vertically, to the floor or grade below shall not permit the passage of a 4-inch-diameter (102 mm) sphere.

In the code there are two sections that address openings related to stairs and they both address openings that are in a vertical position. The only codes that address openings in a horizontal position (floor, stairs or landings) are limited to a maximum 1/2 inch.

2018 IBC
1011.7.1 Stairway walking surface.
The walking surface of treads and landings of a stairway shall not be sloped steeper than one unit vertical in 48 units horizontal (2-percent slope) in any direction. Stairway treads and landings shall have a solid surface. Finish floor surfaces shall be securely attached.

Exceptions:

1. Openings in stair walking surfaces shall be a size that does not permit the passage of 1/2-inch-diameter (12.7 mm) sphere. Elongated openings shall be placed so that the long dimension is perpendicular to the direction of travel.

So as an Architect in your humble opinion where does the walking surface of a tread end? 1" from the guard or 12 inches from the guard or maybe somewhere in between? What would you accept?
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Way nicer than how I said it...
 
Hi all. I thought I would follow up with the final product. The architect designed this solution. The part that is difficult to see is the horizontal window mullion is very wide and effectively prevents you from walking to the side of the stair stringer, so there is not much danger of accidentally stepping on the cables. So, in this case the cables are there to prevent a fall between the stringer and the glass.
20231219_152739.jpg20231219_152727.jpg
 
jpowell said:
Hi all,
Looking for some opinions here. I believe the code is silent to this. IRC 2018.

Let's say we have an interior stairway with a stone wall next to it. The architect doesn't want a guard rail or handrail on the stone wall side. The stair is "floating" so that it has a gap or 3" or 4" to the stone next to it. Another way of saying it is that there is 3" - 4" of space to the side of the treads, between the tread and wall.

What is an acceptable amount of gap allowed beside the tread without a guard? 1" seems fine. No one is getting a foot down a 1" gap. But how/where can this be justified in code?

The riser is a bit easier, as it must be <4".

Question part 2 - compound the issue by doing the same situation next to a storefront window where the glass is an additional 4" beyond the window frame.

Thanks in advance.
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This looks to me like an ACCIDENT READY TO HAPPEN
The Code does not refer to this and extending the "Gap Rules" to include this is more than a stretch
Install the required handrail, so you can maintain your balance ( especially for us "Old People" and use the cable approach you used for the one shown, and you are good to go
 
Just for the record: I agree with mtlogcabin 100%.
That is the way I and all the jurisdictions where I have worked over the past 20+ years have understood it to be.
 
jpowell said:
Hi all. I thought I would follow up with the final product. The architect designed this solution. The part that is difficult to see is the horizontal window mullion is very wide and effectively prevents you from walking to the side of the stair stringer, so there is not much danger of accidentally stepping on the cables. So, in this case the cables are there to prevent a fall between the stringer and the glass.
View attachment 12367View attachment 12368
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This is quite different from what was originally proposed. The original design as said to NOT have stringers at the ends of the treads -- the stringers were to be beneath the treads.

Speaking as an architect, I view this as a typical architect's solution -- more interested in the appearance than in the safety. Quite candidly, I would not want to walk up or down that stair.

What does the guard look like on the opposite side?
 
Thanks everyone for the welcome. Sorry for coming off so salty

jpowell said:
Hi all. I thought I would follow up with the final product. The architect designed this solution. The part that is difficult to see is the horizontal window mullion is very wide and effectively prevents you from walking to the side of the stair stringer, so there is not much danger of accidentally stepping on the cables. So, in this case the cables are there to prevent a fall between the stringer and the glass.
View attachment 12367View attachment 12368
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Question: is the glass guard rated to meet the requirements in 1607.8 per (1015.2.1)?
As well as complying with Section 2407?

The windows are acting as a guard, so they need to be able to withstand linear loads as well as concentrated point loads.

I had to do this on a project recently, we went with extra thick tempered glass. The glazing installer provided extra certifications from the glazing company to the AHJ when we reviewed the submittals.

Also, we ended up with a gap JUST LIKE THAT and went with bolting a metal plate to the top of the stair stringer. Owner wasn't happy with it but it looks better then that cheese grater.
 
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