# Space between stair treads and sidewall



## jpowell (Jan 24, 2022)

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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## Joe.B (Jan 24, 2022)

There's going to be some issues. High heals, crutched, canes, dropped keys, spilled liquids, etc... I don't have the code books in front of me but 1/4" is the first thing that comes to mind, it came up when discussing the surfaces of stairs, such as using separated sheet metal for stair treads.


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## Joe.B (Jan 24, 2022)

*crutches


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## e hilton (Jan 24, 2022)

I would ssk the architect to show where that is allowed.  
Is the storefront glass tempered?


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## Keystone (Jan 24, 2022)

Interpretation, Contact the AHJ....


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## bill1952 (Jan 24, 2022)

If the gap is between a stringer - like a toe board - and wall, I'd say 4" rule. If tread just floats, I don't recall an ICC max opening.  IIRC OSHA says 1 1/2", not sure.


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## tbz (Jan 25, 2022)

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.
> ...


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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## jpowell (Jan 25, 2022)

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.


Good point about the stringers.  There are NO stringers on the sides of the treads.  The stringers would be underneath the stairs.



bill1952 said:


> If the gap is between a stringer - like a toe board - and wall, I'd say 4" rule. If tread just floats, I don't recall an ICC max opening. IIRC OSHA says 1 1/2", not sure.


This might be helpful as support for a requirement of less than 4".  I am not familiar with this standard/guideline.  Can you point me toward where to find this?


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## steveray (Jan 25, 2022)

Tom...where are you getting the 3.375?  <4" I get.....


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## instantmessenger (Jan 25, 2022)

It seems to me that a sphere of 4" would apply whether it is stone or glass (as long as the glass is tempered or laminated) and whether the stringer is open (floating or not) or closed.


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## tbz (Jan 25, 2022)

steveray said:


> Tom...where are you getting the 3.375?  <4" I get.....


Forgive me everyone my typo it should be 4.375, not 3.375.... my bad....

2022 ID IRC Section R312.1.3 opening limitations
                     Exception No. 2

Exception 1 does not apply because there is no bottom of guard to form the triangle with the tread and riser, so falls to exception 2......






						2020 IDAHO RESIDENTIAL CODE | ICC DIGITAL CODES
					

ICC Digital Codes is the largest provider of model codes, custom codes and standards used worldwide to construct safe, sustainable, affordable and resilient structures.




					codes.iccsafe.org


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## steveray (Jan 25, 2022)

Whew....thought I was missing something.....So, yep 4-3/8"......


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## mtlogcabin (Jan 25, 2022)

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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## bill1952 (Jan 25, 2022)

Well, I guess you have to ask if that space between the end of the tread and the wall is a walking surface?

I did not recall correctly regarding floor holes - an opening whose least dimension is 2" or more.  (I see a draft that reduces that to 1" - so my 1 1/2" was an average  )  

I'd say the condition is somewhat unanticipated by the codes.  I just was made aware of another design that I characterize as unanticipated by building codes - making a strong case for more performance and less prescriptive requirements.


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## e hilton (Jan 25, 2022)

bill1952 said:


> Well, I guess you have to ask if that space between the end of the tread and the wall is a walking surface?


Good question.  I think it has to be treated as a walking surface because it is an extension of the physical walking surface.  An old person with mobility problems could get too close to the edge and step off, the legs of their walker could fall into the gap, all kinds of unpleasant options.


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## bill1952 (Jan 25, 2022)

Always a hard sell to say a non-surface is a walking surface. That condition exists on a lot of social stairs.


			https://i.pinimg.com/originals/60/03/fd/6003fddff5225fb2f8c4ee6ec6479070.jpg


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## ADAguy (Jan 25, 2022)

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.


Nice point
Also, is he using handrails, or not?
He is looking at too many magazine ads showing noncompliant stairs.


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## Inspector Gift (Jan 25, 2022)

I agree with Mtlogcabin's position .   We have encountered the same question regarding exterior, residential stairs several years ago.  And we concluded that unless there is a guard guardrail system, the open space between stair treads and the wall can not exceed 1/2".


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## tbz (Jan 25, 2022)

mtlogcabin said:


> 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:
> ...


Mt, we will have to agree to disagree on this one, not to often, but once the tread ends it is no longer a walking surface, and there is no walking surface on the other side of the gap.

You can't have it both ways, the guard is not part of the walking surface, ie the tread, as thus openings in guards' are allowed to be up to a point of not passing a 4.375" sphere.

I might not like It but, you can't call the opening space on the guard's offset from the walking surface, walking surface if there is no floor on the other side, an opening in the floor, it ended, and now its the guards job to close it off......

Edit: 1/26/22

additionally, how is this any different if allowed....both are in place for the same reason....






Pic borrowed from another thread...

LINK TO: No landing outside exterior door....thread


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## steveray (Jan 26, 2022)

I have no issues with MT's interp and admire that he can....here, the State does that...I agree it gets a little sketchy, just don't know if it is a "real" problem that the IRC needs to address or not...


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## tbz (Jan 26, 2022)

steveray said:


> I have no issues with MT's interp and admire that he can....here, the State does that...I agree it gets a little sketchy, just don't know if it is a "real" problem that the IRC needs to address or not...


? So how is the door sill any different than the edge of a tread? 

is it because you feel one is perpendicular to travel direction and one is parallel?

If the door sill is not higher than the maximum allowed, is not the sill the walking surface and as thus continuous walking surface right to the edge.

Adding Edit:

MT, if we follow your logic in the other post is it not a contradiction here from your conclusion.  You allow the floor level door/window opening to have the 4"-sphere opening space for the guard there, but when an actual window or wall is in place you change to the 1/2" gap.  

Using the logic from the other post, neither area can be stood on.  

Again, looking for information for presenting in my lectures and explaining how inspectors are (enforcing) the code, and what makes the situations different.

Not picking a confrontation, enjoy the day everyone.....Tom


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## steveray (Jan 26, 2022)

I think those folks that are "enforcing the gap" are concerned about accidental entrapment or trip/ fall.....Which is less likely when you are expecting a "drop" at a step/ threshold in the direction of travel than a "crack" at the side of a tread....I see the concern, but I have never seen it be a problem.....


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## tbz (Jan 26, 2022)

So again not picking confrontation, but a typical side mounted glass railing with 1.25" of standoffs space between edge of tread glass would be the same as a wall, allowed or not and why not the 1/2" interp enforced here, there has to be a number to activate a over enforcement reach?

I get the sidestep opening, but just because one might not like it, one is inserting personal feelings into something that is personally wanted.


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## steveray (Jan 26, 2022)

Got a pic Tom? Or drawing?


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## mtlogcabin (Jan 26, 2022)

tbz said:


> one is inserting personal feelings into something that is personally wanted.


My understanding of the original post there is neither a guard or a handrail on the rock wall side of the treads, just a 4" gap between the end of a step and the wall. The IRC is a prescriptive code for what is typical in a SFR or 2 family dwelling. The IRC is silent on this specific design. So a BO uses R104.1 to render an interpretation and adopt a policy for that specific design. I look to the other codes adopted or not past or present to render my decisions

"It is important to understand that the IRC contains coverage for what is conventional and common in residential construction practice. While the IRC will provide all of the needed coverage for most residential construction, it might not address construction practices and systems that are atypical or rarely encountered in the industry."


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## e hilton (Jan 26, 2022)

tbz said:


> additionally, how is this any different if allowed....both are in place for the same reason....


Actually, they are not for the same reason.  The balcony rail is to keep you from walking through the doorway, to keep you from crossing the threshold.  The stair handrail is to keep you on the walking surface as you move along the path.


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## Inspector Gift (Jan 26, 2022)

steveray said:


> I have no issues with MT's interp and admire that he can....here, the State does that...I agree it gets a little sketchy, just don't know if it is a "real" problem that the IRC needs to address or not...


This is really a question of open gaps in a floor surface, particularly applicable to the open gaps in decking and stair treads - which is not addressed in the IRC.

We look at this as a question of a missing guards - not missing guardrail or riser opening.    And it is addressed in the IRC. 

We decided the question has to do with an open gap in a walking the surface.  We determined that it was a safety hazard, and supported our position based upon the vertical height above the grade below.   Anywhere the open space between the treads (standing surface) and the grade level exceeded 30 inches a guard rail was required.  (R312.1.1)   In lieu of providing guards on the wall side, we suggested the builder extend the treads within 1/2" of the wall, (using the tolerance allowed for in the IBC).   

So, why is the IRC silent on the spacing between deck boards at decks and deck stairs?

 [Attention: GLEN MATTEWSON - the Deck Code Guru]


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## jpowell (Jan 26, 2022)

Thanks for the input, everyone!  As the AHJ, I will make an interpretation based on R014.1


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.


I agree with what you guys are saying, and I wish the code was more clear on it.  I am going to go with:
1. There is no guard on the side with the wall.
2.  R312.1.1  ...guards are required on the open sides of walking surfaces, stairs...
3.  R312.1.3  Opening limitations - treating the wall/safety glass windows as the guards, therefore an opening of <4" allowed.


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## Joe.B (Jan 26, 2022)

I was told that someone somewhere (probably CA) was injured when their high-heel got lodged into a gap in a walking surface. They successfully sued the property owner and gaps in walking surfaces were added to codes. It would make sense that IRC would not address this because it doesn't cover "public accommodations" and the like.


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## mtlogcabin (Jan 26, 2022)

Guards are a vertical protection from a horizontal fall not a horizontal protection from a hole in the floor, step or landing.


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## e hilton (Jan 27, 2022)

mtlogcabin said:


> Guards are a vertical protection from a horizontal fall not a horizontal protection from a hole in the floor, step or landing.


Ok, then let’s call this situation a gap in the walking surface.


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## bill1952 (Jan 27, 2022)

e hilton said:


> Ok, then let’s call this situation a gap in the walking surface.


OSHA calls them to floor holes.


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## bill1952 (Jan 31, 2022)

And just for some fun on the stair topic https://weburbanist.com/2008/11/26/creative-modern-stairs-staircase-designs/

I especially liked Stairs for a Super-Tight Space about halfway down.


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## tbz (Jan 31, 2022)

bill1952 said:


> OSHA calls them to floor holes.


Floor holes are not under the stair section in OSHA, not addressed in OSHA Bill.


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## bill1952 (Jan 31, 2022)

1910.23(a)(9) refers to floor holes. One of their standard interpretations says: OSHA's construction fall protection rule, 29 CFR Subpart M §1926.500, defines these terms as follows: "Hole means a gap or void 2 inches (5.1 cm) or more in its least dimension, in a floor, roof, or other walking/working surface." Certainly a stair is a walking surface.

While labeled a draft this document from OSHA clarifies intent: 

"Definitions used in 1910.23 (arranged alphabetically by the respective paragraph)

Floor hole: an opening measuring less than 12 inches but more than 1 inch in its least dimension, in any floor, platform, pavement, or yard, through which materials but not persons may fall; such as a belt hole, pipe opening or slot opening. 

Floor opening: an opening measuring 12 inches or more in its least dimension, in any floor, 
platform, pavement, or yard through which persons may fall; such as a hatchway, stair or ladder opening, pit or large manhole. Floor openings occupied by elevators, dumb waiters, conveyors, machinery, or containers are excluded from this subpart."

Of course they conflict - 1" or 2" - but that's federal rule making.


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## redeyedfly (Feb 1, 2022)

e hilton said:


> I would ssk the architect to show where that is allowed.


You have this backwards.  The reviewer must show the architect where it is not allowed in code.  Innocent until proven guilty and all...


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## e hilton (Feb 1, 2022)

redeyedfly said:


> You have this backwards.  The reviewer must show the architect where it is not allowed in code.  Innocent until proven guilty and all...


But the architect should use reasonable efforts to design to code.  Considering the amount of discussion in this thread, it may or may not be correct.  I would still ask the archy what his design basis was.


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## bill1952 (Feb 1, 2022)

Stairs are no. 1 for injuries, according to CPSC's NEISS reporting system. Probably in the $100 billion a year range in cost to society (just residential). The architect is obviously focused on aesthetics and the particular condition - an unguarded fall hazard at side of a waking surface might be a hazard.  Are these residential? Only stairs between these levels? How wide? Functional - truley graspable - handrail on the other side? Good visibility and uniform rise and run including first step from landing? It might not be a hazard requiring mitigation.  (Were I the official based on what's here - 2" max - but never will be my call.)

Never will have a code that can fairly address all designs and never stop designers from wanting different and never seen before. ( And on many days my response to "never seen before" is "there is a damn good reason!")


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## my250r11 (Feb 1, 2022)

I can see the logic in the definitions from OSHA but find it hard to apply to SFD.


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## tbz (Feb 1, 2022)

bill1952 said:


> 1910.23(a)(9) refers to floor holes. One of their standard interpretations says: OSHA's construction fall protection rule, 29 CFR Subpart M §1926.500, defines these terms as follows: "Hole means a gap or void 2 inches (5.1 cm) or more in its least dimension, in a floor, roof, or other walking/working surface." Certainly a stair is a walking surface.
> 
> While labeled a draft this document from OSHA clarifies intent:
> 
> ...


Bill, not going into long hand but 2 of my good friends both are Fed OSHA inspectors, one is a senior accident inspector.

When I ran this question by them, the first thing they both said to me was, not addressed for stairs, walking surfaces per their does not link with stairs, they are 2 different sections.

So you can imply all you want to the issue of intent, but those that inspect for it, said they have nothing to hold to...stairs are not part of walking surfaces per them.

Also OSHA is not for residential, which this clearly is, thus again they said the gap would not exist in their field, as if the stair flight needed guards it would also need handrails on both sides, as thus if the inside of the handrails are over the stair treads and the gap is less than 21, their good.


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## bill1952 (Feb 1, 2022)

OSHA is indeed not for residential (unless you're an employee working there) but the terminology seemed to be applicable.  Comparing the open horizontal surface to a vertical surface like a guard or riser makes no sense.

Any suggested code language for next cycle?


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## ADAguy (Feb 1, 2022)

bill1952 said:


> OSHA is indeed not for residential (unless you're an employee working there) but the terminology seemed to be applicable.  Comparing the open horizontal surface to a vertical surface like a guard or riser makes no sense.
> 
> Any suggested code language for next cycle?


Kids don't know the difference, only that they are naturally curious and will attempt to insert themselves into any space.
Best practice says don't do it, an Atty sees $$$ signs.


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## bill1952 (Feb 2, 2022)

So is the consensus here code requires a full guard meeting 4" sphere requirement on the side with 4" gap between tread end and stone wall/glass window?


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## jpowell (Feb 3, 2022)

bill1952 said:


> So is the consensus here code requires a full guard meeting 4" sphere requirement on the side with 4" gap between tread end and stone wall/glass window?


That is what I went with.  Though I can see someone requiring a tighter gap as well.

Thanks everyone for the great discussion!


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## bill1952 (Feb 3, 2022)

jpowell said:


> Though I can see someone requiring a tighter gap as well.


Sorry, just to clarify, in place of or in addition to compliant guard?


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## jpowell (Feb 3, 2022)

bill1952 said:


> Sorry, just to clarify, in place of or in addition to compliant guard?


There is no guard or handrail on the wall side.  (The side we are discussing.)


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## bill1952 (Feb 3, 2022)

jpowell said:


> There is no guard or handrail on the wall side.  (The side we are discussing.)


Sorry, I understood you to say you went with a full code compliant guard.  Not clear now on what you did go with.


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## jpowell (Feb 3, 2022)

bill1952 said:


> Sorry, I understood you to say you went with a full code compliant guard.  Not clear now on what you did go with.


I misread your post.  There is no guard.  I required the gap between the tread and wall to be less than 4".  Actually, let me rephrase that.  The architect specified a gap of less than 4", and I approved it.


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## bill1952 (Feb 3, 2022)

jpowell said:


> I misread your post.  There is no guard.  I required the gap between the tread and wall to be less than 4".  Actually, let me rephrase that.  The architect specified a gap of less than 4", and I approved it.


Got it. Thank you.


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## Genduct (Feb 5, 2022)

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.


I was thinking the same thing.  Using the same standard is certainly reflecting the INTENT of the Code
Well Done


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## Rick18071 (Apr 11, 2022)

What ever this means. 
Stairway treads and landings shall have a solid surface. 

If there is a space is it  solid?


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## steveray (Apr 11, 2022)

Rick18071 said:


> What ever this means.
> Stairway treads and landings shall have a solid surface.
> 
> If there is a space is it  solid?


Isn't all matter made of space?


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## bill1952 (Apr 11, 2022)

Rick18071 said:


> What ever this means.
> Stairway treads and landings shall have a solid surface.
> 
> If there is a space is it  solid?


Is the space to side of stairs a tread?


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