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Space between stair treads and sidewall

jpowell

Bronze Member
Joined
Mar 16, 2012
Messages
41
Location
McCall, ID
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.
 
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.
 
I would ssk the architect to show where that is allowed.
Is the storefront glass tempered?
 
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.
 
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.
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.
 
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.

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?
 
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.
 
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......

 
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.
 
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.
 
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.
 
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.
 
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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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.
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....

1643149009597-png.8527

Pic borrowed from another thread...

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