# Walking surface ends and guard begins



## tbz (Mar 21, 2011)

Good morning to all on this snowy Monday morning.

This question comes to me at least 3 times a week and I seem to be getting more and more and well would like others opinions on this.

As an inspector weather IBC or IRC, how do you define the end of the walking surface to where a guard begins as compliant?

More and more architects are designing guards to hang off the side of the walking surface.  This brings up the following questions

1. Is the floor space allowed to stop before the protection of a guard begins?

2. If so how do you measure for this, 4" sphere between bottom of guard and floor, thus allowing 3.875" of open floor when the bottom of the guard is level with the floor surface?

3. How would you handle second floor roof deck, 3" gutter then guard begins?

4. Do you figure this different for level walking surfaces like decks than for stairways?

I am trying to establish a common agreement for in the field, this seems to greatly vary from town to town and state to state, all input is welcomed and so to additional questions if you don't follow my badly worded question.

Thanks - Tom


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## Rick18071 (Mar 21, 2011)

If is an accessible space I would say no more than 1/2"( ANSI 2003 302.3 ).


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## tbz (Mar 21, 2011)

ok, 58 views 1 reply lets try a sketch or two.

The 3 sketches below comply (yes/no) if no why not?







Rick, lets follow your note why only accessible and if not required accessible how big an opening allowed in floor or at edge?


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## peach (Mar 21, 2011)

a required is a required guard whether its the open side of a stair or deck.  Whatever it's hanging off of needs to be able to support it (the outside of a gutter?).  It doesn't matter what dimension you use - it needs to prevent passage of a 4" solid sphere.


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## tbz (Mar 21, 2011)

So peach the open space in the floor between the edge of the floor and the guard is allowed, as long as, it does not allow passage of a 4" sphere to fall through and down?

It also does not matter if it is on a stair, ramp or walking surface?


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## Yikes (Mar 21, 2011)

The purpose of guardrail is to prevent walking into an area where vertical fall can occur.  I believe that code is that the guardrail gap (the vertical plane) must be less than 4", and the tread / walking surface must be not exceed 1/2" gap.

Therefore, going counterclockwise in the sketches:

Lower left: no, because the 1" gap in the walking surface is greater than 1/2".  High heel could theoretically get caught here. (Could've been fixed just by bringing out the drip flashing another 1/2".)

Lower right: no, because the 3 3/4" gap in the walking surface is greater than 1/2".  A narrow foot could fall through.

Upper right: no, because even though an adult may be kept within the walking surface area, a little kid reaching up to grab onto the rail may step underneath the overhanging handrail above, and thus is exposed to the 3 1/2" gap in the walking surface (which is greater than 1/2").

I realize this is different than my opinion of a week ago in a different thread.

IMO it does not matter if it is a stair, ramp or walking surface.


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## RLM-Architect (Mar 21, 2011)

Yikes nailed it.  'NUFF SAID.

The architects that come up with this goofy stuff need fixin'.  Nowhere in any Code does it give permission to provide openings in a horizontal walking surface that exceeds 1/2" and that would ONLY be in industrial or storage type occupancies on stairs and grated landings and catwalks where no children would typically be present.


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## jeharrarch (Mar 22, 2011)

Sorry to (maybe) beat a dead horse but isn't the 1/2" maximum opening in floor surfaces an element of accessibility and promulgated by the ADA (codified by the acceptance of ANSI A-117 in the IBC) - implied by Rick? If so, then any area not required to be accessible (such as a balcony on a story which is less than 3000 sf) would not be governed by this and, therefore, the 4" sphere guard requirement would apply (as Peach indicates). What the question really gets to is the idea of edge protection - which is only dealt with in the ADA in respect to ramps (and recreational facilities). If the example were an accessible fishing pier, the answer would be simple (ADA-AG 1005.3). To play Devil's advocate, in the absence of threat of a wheelchair wheel or crutch slipping off the side of this balcony/deck/whatever (i.e. a space not required to be accessible), I don't think anyone could argue that a series of vertical balusters complying with the 4" sphere limitation, attached to the fascia of the deck (without a lower horizontal rail), and extending up to create a guard would be contrary to the code. This would then create an equally dangerous series of openings that childrens' feet could easily slip through. That said... It seems that the spirit of Yikes' and RLM's posts are correct - the danger of slipping vertically is certainly there.

I agree that the design generates a very significant liability concern for the design professional, but I'm not sure that any of the diagrams above are expressly prohibited by the code (assuming no requirement for accessibility to the location).

Hope that made some sense...and please correct me if I'm looking at this all wrong.

My first post, ever!


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## High Desert (Mar 22, 2011)

Great first post. I would agree with your analysis.


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## tbz (Mar 22, 2011)

Ok,

RLM not enough said need to go a little deeper.

JEH, welcome to the board and your input is welcomed and a reason for my question in the first place.

Yikes,

I agree with all your statements, the floor needs to be protected from someone walking off the edge when over 30" above the landing area below.

However, as you can see many would allow the opening only restricted by the 4" sphere.

This also comes up a lot with me on IRC, exterior small balconies with large openings over 1/2", the code requires there be a landing, yet the inspectors don't require the landing to meet the 1/2" sphere, thus I ask why not?

With, all the views and I know this crowd has some opinions, please chime in on your view, I am not looking to hold anyone to a certain point, just trying to get more input and discussion on this IMPORTANT field issue.

Please comment....


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## Yikes (Mar 22, 2011)

JEH, welcome!

1.  I believe the 4" sphere comment is for guards, which are designed to resist a horizontal motion, not a vertical fall.  That's why in IBC 1607.7.1.2 the 50 lb. load is applied horizontally, not vertically.  Anyone weighing over 100 pounds would put more than 50 lbs of vertical force on a walking surface, thus invalidating the guard engineering.

2.  The example you gave about the story under 3000 Sf does not exempt the balcony from all accessibility features. It only exempts it from requiring a (wheelchair-acessible) path of travel from the public right of way (ramp, elevator, lift, teleporter, etc.).  A person who uses a cane or other mobility device may still use the stair.  In fact, they me more likely to walk very close to the handrail.

3.  In last week's thread titled "Walking surface", fatboy quoted IBC 1009.6.1 for stairways.  I realize this does not apply to balconies, but there you have a code rationale that is based on life safety, not accessibility.

Most people would agree that a 3 7/8" spacing of bars on a balcony walking surface would not be acceptable.  At some point as the surface plane in question is rotated / becomes more vertical, it becomes more reasonable, until finally all would agree it meets code as a vertical guardrail.

I agree that it is unlikely that  a person would fall through the example in the lower left corner of tbz's sketch, but all I'm saying is that it goes beyond the prescriptive requirements of the code.  Why take the chance?  You could easily retrofit a fix to that scenario.

P.S. Enjoy the following photo link.

http://cache2.asset-cache.net/xc/79572137.jpg?v=1&c=IWSAsset&k=2&d=D4DA32DF5F8999C330F60B823F3BA1B67CEE58882EDCF475C632E1CB0AEE4941E30A760B0D811297


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## High Desert (Mar 22, 2011)

Yes, Section 1009.6.1 is for stairways and should be limited to stairways because that's what the code says. I'm not sure how you could make that apply to the most outer edge of a deck. That's like applying the stairway handrail requirement to the deck guardrail.

I would not agree that the edge of the deck would be a vertical guardrail, it's simply the edge of the deck.

I am not disagreeing that Tom's examples are the ideal way of constructing a guardrail, but I do think someone needs to clearly identify a code section that regulates the specific scenario.


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## mtlogcabin (Mar 22, 2011)

1013.3 Opening limitations.

Required guards shall not have openings which allow passage of a sphere 4 inches (102 mm) in diameter from the walking surface to the required guard height.

This section does not allow an opening in the floor surface it allows the opening in the guard.

Agree with Yikes non of the examples are code compliant


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## High Desert (Mar 22, 2011)

Yikes said:
			
		

> JEH, welcome!1.  I believe the 4" sphere comment is for guards, which are designed to resist a horizontal motion, not a vertical fall.  That's why in IBC 1607.7.1.2 the 50 lb. load is applied horizontally, not vertically.  Anyone weighing over 100 pounds would put more than 50 lbs of vertical force on a walking surface, thus invalidating the guard engineering.
> 
> 2.  The example you gave about the story under 3000 Sf does not exempt the balcony from all accessibility features. It only exempts it from requiring a (wheelchair-acessible) path of travel from the public right of way (ramp, elevator, lift, teleporter, etc.).  A person who uses a cane or other mobility device may still use the stair.  In fact, they me more likely to walk very close to the handrail.
> 
> ...


Yes, Section 1009.6.1 is for stairways and should be limited to stairways because that's what the code says. I'm not sure how you could make that apply to the most outer edge of a deck. That's like applying the stairway handrail requirement to the deck guardrail.

I would not agree that the edge of the deck would be a vertical guardrail, it's simply the edge of the deck.

I am not disagreeing with you and saying that Tom's examples are the ideal way of constructing a guardrail, but I do think someone needs to clearly identify a code section that regulates the specific scenario.


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## Yikes (Mar 22, 2011)

Thanks high desert.  I did not mean to imply that the edge of the deck would _actually __*be*_ a vertical guardrail.  Instead, I was playing a hypothetical mental game wherein a flat surfaced walking deck with gaps in it is bent upwards (like in the movie Inception) until we start thinking of it more like a guardrail instead.


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## Rick18071 (Mar 22, 2011)

IBC 1604.2 Strength. Buildings and other structures, and parts thereof, shall be designed and contructed to support *safely* the factored loads..........

If there is nothing there, then there is no support of the required loads for a floor.


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## Examiner (Mar 22, 2011)

The balcony has a floor and the floor is the walking surface until it is guarded.  The rail is the guard and the toe space / edge protection is in the vertical plane not the horziontal plane.  The 4" sphere rule is the vertical plane not the horizontal plane.  The detail is in error by leaving a gap in the horizontal plane.


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## tbz (Mar 22, 2011)

Examiner said:
			
		

> The balcony has a floor and the floor is the walking surface until it is guarded.  The rail is the guard and the toe space / edge protection is in the vertical plane not the horziontal plane.  The 4" sphere rule is the vertical plane not the horizontal plane.  The detail is in error by leaving a gap in the horizontal plane.


Examiner the details are of projects drawn by architects all the time, my question is is the horizontal space compliant or not and if not explain why not and the same if you say it is compliant.

I believe that the floor opening is non compliant because floors are not allowed to have 3 in holes in them I think, but can't back it up with a code section.


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## jeharrarch (Mar 22, 2011)

Yikes - i appreciate the morphing walking surface/guard - that's a great mental image...

Ignoring issues of accessible routes, the purpose of the guard, it seems to me based on the code commentary, is to prevent the building occupant from falling through the guard to the level below, avoiding serious injury. So the length of the fall is important, otherwise, all edges of walking surfaces would require a guard, not just where the grade or floor is > 30" below. In occupancies where kids are likely to be, the 4" sphere is what has been deemed appropriate to prevent them from falling completely through the balusters. Because there is no specific requirement for edge protection for a guard (only for ramps), it seems reasonable that as long as the guard prevents the occupant from falling completely through and to whatever hard surface is below, it has done its code (minimum) mandated job... Examiner, while I agree that it's a problematic detail at best, I can't see where the letter of the code defines the 4" sphere rule specifically / solely in the vertical plane. Tom, the edge of the balcony seems like it is the edge of the balcony, so there's not really a 3" hole in the floor... the guard, to me, is it's own separate thing but I don't have a code section to back that opinion up - see below, though.

The example Yikes posed is really interesting. The code does not mandate a guard to be 90 degrees from the adjacent walking surface. So if we imagine vertical balusters rising from the horizontal edge of the balcony angled at 60 degrees (or so) from horizontal and complying with the 4" sphere rule, an occupant could easily step through the gap between the rails. They would be prevented from completely falling through to the level below, though, due to the 4" space - but this is more or less the same thing that would happen with a purely vertical guard as well as in Tom's diagrams. In other words, it's bad and liability ridden design - but code compliant. (of course, that's also just my opinion)... Thoughts?


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## Yikes (Mar 22, 2011)

You know what's really great?  I you try to Google "openings in walking surfaces" to find out what the rest of the world thinks on this subject, the first result takes you right back to this forum.


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## Examiner (Mar 23, 2011)

http://www.osha.gov/pls/oshaweb/owadisp.show_document?p_table=STANDARDS&p_id=9715

OSHA toe board or toe guard.

The edge protection is to prohibit items from rolling under the guard's bottom rail which might injure someone below.  The Code has the 4" sphere rule that would be between the horizontal bar of the guardrail's bottom bar vertically above the floor surface.  ADA and the building Code both address the floor openings such as grate openings being limited to 1/2".  If the gap between the guardrail and edge is more than a 1/2" in the horizontal plane then a walking cane or high heel would go through.  All graphics in the ADA and Code show the guardrail is directly above the walk surface and not beyond the edge of the walk surface.  In my opinion OSHA would cite the edge detail as a violation.  Professionals are also to keep in mind requirements of OSHA in their designs.


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## jeharrarch (Mar 23, 2011)

Thanks, Examiner - really good info on OSHA and one that I didn't even consider. I completely agree that design professionals need to be cognizant of all of the various requirements that are out there and especially with the concern for disabled employees... Maybe edge protection should be more widely incorporated in the ADA and IBC beyond ramps. The graphical representations of guards in the IBC and ADA are generalizations and can't be assumed to be the only permissible solution. The (IBC) Code never states that the guard must be in any relationship to the edge of the floor, only that a 4" sphere can't pass through it. That said, the arguement I would make for having to allow the detail is three-fold:

I would argue that the detail does not show a 3-1/2" opening in a floor surface, but rather that it is a gap between an edge of a floor surface and a guard (the IBC allows unguarded vertical changes in elevations, and specifically denotes them "open sided walking surfaces" of up to 30") - in other words, the guard is not part of the floor.

Applying this to an occupancy where Labor regulations are applicable, based on OSHA 1910, I'd call the edge of the balcony an "open sided floor" rather than a "floor hole", and governed by (1019.23©). Let's assume a balcony off of a lawyer's office - not a typical industrial plant, but certainly a place with employees and, one could easily argue, regulated by OSHA as well as the IBC. Take Tom's 1st sketch. There is a 3-1/2" opening between the end of the open sided floor and the beginning of the guard (as OSHA defines, railing, or as the IBC defines, guard). Clearly this does not allow persons to fall through, lawyers don't possess any moving machinery, and there is no equipment nearby - therefore, no toeboard required (per 1910.23©1:i,ii, & iii). But even if the lawyers had some moving machinery close by, the only additional element to make Tom's first sketch compliant with OSHA would be a 4" toeboard at the edge of the balcony. There could still be a vertical gap between the toeboard and intermediate rail of about 17" (21" from floor to the intermediate rail minus 4" of toeboard) - which is a pretty big hole for someone to fall through - much larger than the 3-1/2" horizontal gap in Tom's sketch. However, if we're using OSHA, there is no 4" sphere rule (correct?) but this would violate the IBC - so if we're being especially stringent the maximum distance between the toeboard and the guard would be <4" - just like the sketch. An aside, the OSHA regulation does not include any language as to elucidate the location of the rail as related to the edge of the open sided floor - it is much less clear than the IBC. But its job is the same as defined: "...to prevent falls of persons".

If the condition were proposed in a single family residence, edge protection (and OSHA) wouldn't apply. It's back to whether the Code allows, where a guard is otherwise required, any gap such that a 4" diameter sphere can pass through any opening... The detail does not allow the passage of the sphere, and therefore complies.

I really hate to argue (at length) for something that I think is especially poor design, but I just can't agree that the Code forbids this detail. I'll just have to respectfully disagree with those who respectfully disagree with me, and leave it at that!!


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## Glennman CBO (Mar 24, 2011)

I agree with jeharrarch. To call it a hole in the floor that exceeds 1/2" is a streach.

I've seen this before. As a matter of fact, it was at a local vocational school that I finaled. My daughter started attending there, and she told me about how the chair leg that was at some tables near this guard at a second floor seating area would go off the edge and get caught in the guard. I made a site visit and concluded that, yes, it may be a bad design, but there is no specific code section that can be used to prohibit it.

If this was a floor area (using the max 1/2" opening arguement), and you installed a 4" "curb" then one could argue that you cannot have a 4" curb in a floor area (I supppose it would need to be max 1/2" high with 2/1 slope like a threshold. Obviously not). The whole floor area arguement is flawed, IMHO.


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## High Desert (Mar 24, 2011)

tbz said:
			
		

> Examiner the details are of projects drawn by architects all the time, my question is is the horizontal space compliant or not and if not explain why not and the same if you say it is compliant.I believe that the floor opening is non compliant because floors are not allowed to have 3 in holes in them I think, but can't back it up with a code section.


That's just the point. There is no code section to cite for noncompliance. It's not a hole in the floor, but a compliant gap at the bottom of the guardrail.


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## Yikes (Mar 24, 2011)

Glennman, I see what you're saying, and your example from the vocational school is a perfect real-world scenario.  The 1/2" hole in the floor may sound like a stretch, but it neatly fits the actual problem: a floor surface that is inadequately designed to support a reasonable load.

And you CAN have a curb within the space of a floor area, as long as no one is intended to travel across the curb.  (A built-in seat is a type of giant curb.)  The fact that the curb would be close to the perimeter of the seating area at the vocational school would make it an unlikely path-of-travel or trip hazard.

Your curb example is not that far off from the description of a baseboard, which is not a walking surface but is a maintenance / wall finish device.


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## Glennman CBO (Mar 24, 2011)

Yikes,

Maybe my curb analogy has some flaws, but the point I'm making is that either it is a floor area, or it is not (at the gap between the floor and the guard).


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## Yikes (Mar 24, 2011)

Agreed.  In the example of a chair leg falling downward, one or more failures are occuring:

1.  There is inadequate floor coverage, and the leg is falling vertically _through the floor_.

2.  There is inadequate guardrail coverage, and the leg is pushing horizontally _through the guardrail_ area into a _non-floor_ space where it can fall vertically.

3.  The unusual use* of the code-compliant "gap" is unanticipated in the code. By this I mean that an _angled_ chair leg that can slip at an angle between floor and guard)

Prudent design ("loss prevention") would be to eliminate #1 and 2 as possible targets in a legal action.  The best way to do this for the floor is to not leave a gap that is 1/2" or larger when seen in plan view.


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## High Desert (Mar 24, 2011)

Yikes,

There is no legal action if it's not a code requirement. "Unanticipated in the code" is not a reason to skew the code requirements to fit your opinion. By requiring something that is not in the code is painting a "target for legal action" on your own back.

I do agree that it is not addressed in the code and should be. The way to change it would be a code change to ICC, or if your state or jurisdiction permits it, a local amendment.


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## jeharrarch (Mar 24, 2011)

Yikes - I agree too, especially with the "prudent design". But couldn't you make identical arguments for a guard with the following geometry (which I would say complies with the IBC): vertical pickets attached to the floor edge at <4"? A chair leg could easily fall vertically through (the edge of) the floor or horizontally through the guard into the "non-floor" space. (really sketchy sketch here)Does this, I would venture to say very common, detail also not meet Code?  I would say it does, because it prevents the chair and its occupant from falling all the way through and hitting the ground below. Just because an item smaller than a 4" sphere can pass through an opening in a guard doesn't make a difference - whether in the vertical or horizontal plane. The purpose of a guard it to prevent a person from falling to the surface below... which this and the OP's detail both do. Not good, but permitted.

View attachment 422


View attachment 422


/monthly_2011_03/572953bfb335a_guardwithoutbottomrail.jpg.ea59b43404a76a95a54afab6a7bc6c1c.jpg


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## Big Mac (Mar 25, 2011)

I could find no definition of floor in the IBC, therefore as directed by code, I attempted to determine the intent of the code by finding its common meaning.  The following definitions were found on line rather readily and I think provide a common sense direction to the intent of a floor system.

•	The surface on which one walks

•	A continuous supporting surface

•	A level supporting surface

•	A level area for a particular use

•	The surface of a room on which one stands

It seems quite clear that there was never the intent that a floor surface would have portions unsuitable for the stated purposes, such a walking.  There may be several reasons for this, not the least of which is life safety, one of the basic tenants of the code.  It seems unrealistic to me that much of any gap is acceptable.  I guess I could somewhat go along with the 11/2” stated except that even that allowance is for a limited opening length, like two inches.

Any opening greater than ½” should be considered unacceptable.

Definition of floor, per dictionary .com

floor:

1.

that part of a room, hallway, or the like, that forms its lower enclosing surface and upon which one walks.

2.

a continuous, supporting surface extending horizontally throughout a building, having a number of rooms, apartments, or the like, and constituting one level or stage in the structure; story.

3.

a level, supporting surface in any structure: the elevator floor.

4.

one of two or more layers of material composing a floor: rough floor; finish floor.

5.

a platform or prepared level area for a particular use: a threshing floor.

6.

the bottom of any more or less hollow place: the floor of a tunnel.

Definition of floor, free dictionary

floor   (flôr, fl r)

n.

1.

a. The surface of a room on which one stands.

b. The lower or supporting surface of a structure.

2.

a. A story or level of a building.

b. The occupants of such a story: The entire floor complained about the noise.

3.

a. A level surface or area used for a specified purpose: a dance floor; a threshing floor.


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## Yikes (Mar 25, 2011)

jeharrarch said:
			
		

> Yikes - I agree too, especially with the "prudent design". But couldn't you make identical arguments for a guard with the following geometry (which I would say complies with the IBC): vertical pickets attached to the floor edge at <4"? A chair leg could easily fall vertically through (the edge of) the floor or horizontally through the guard into the "non-floor" space. (really sketchy sketch here)


Yes, your sketch meets code, and a chair could still fall through.  I think we're making the same point.  I'm thinking of it more from a standpoint of CYA loss prevention, in addition to the actual safety issue.

The reason for a prescriptive code is that society agrees it provides a reasonable standard for minimum amount of safety; the flip side of this is that it allows a socially / legally acceptable amount of risk.  If the chair legs in your sketch fall through the (code compliant) floor+guardrail, and the person in the chair breaks their teeth on the pickets, the ambulance-chasing lawyers will have a difficult time proving that a code compliant design was also professionally negligent design.

On the other hand, if the chair falls through a gap > 1/2" in the floor, or next to the floor, the code is no longer providing you safe harbor.  You've seen the varying opinions in this thread; now imagine we're all the expert witnesses giving depositions in a lawsuit.  That's a gap that a jury can fall through, too.


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## High Desert (Mar 25, 2011)

If I had to worry about being sued for everything that is not clearly addressed by the code, I would have changed occupations 20 years ago.

You have your opinion on the subject, and I respect that. But I still don't agree that it's a clear code violation. And in a court of law, that's exactly what my stance would be.


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## Yikes (Mar 25, 2011)

Well, I actually hope I'm wrong, but I'd rather play it conservative on this one.


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## tbz (Mar 28, 2011)

Ok, I see the point everyone is making, the floor ends, clearly defined and then the guard protects.

Let me ask you this question now, what about in the 09 IRC, R311.3 which requires a floor or landing be on each side of an exterior door.

Example: Homeowner pulls out a window on the second floor and installs a french door.  then proceeds to install just a guard, does not the exception in R311.3 still require the landing, it just allows the landing to be less than 36"?

Or do you still allow just the guard with opening below it because zero is less than 36"?  Code section listed below for reference.



> R311.3 Floors and landings at exterior doors. There shall be a landing or floor on each side of each exterior door. The width of each landing shall not be less than the door served. Every landing shall have a minimum dimension of 36 inches (914 mm) measured in the direction of travel. Exterior landings shall be permitted to have a slope not to exceed 1/4 unit vertical in 12 units horizontal (2-percent).Exception: Exterior balconies less than 60 square feet (5.6 m2) and only accessible from a door are permitted to have a landing less than 36 inches (914 mm) measured in the direction of travel.


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## High Desert (Mar 28, 2011)

Isn't zero less than 36?


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## brudgers (Mar 28, 2011)

tbz said:
			
		

> Example: Homeowner pulls out a window on the second floor and installs a french door.  then proceeds to install just a guard, does not the exception in R311.3 still require the landing, it just allows the landing to be less than 36"?


What is the difference between a french door and a large casement window?


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## Glennman CBO (Mar 29, 2011)

I think in the case of the french door...the code assumes that if there is an exterior door, that it will be used for some kind of egress in and out of the residence.

If they want to install a french door on the second floor with nothing but a guard on the outside, more power to them.

If they did it on the 1st floor, and they installed a guard in the same fashion, I would not require a landing there. The guard screems "This door will not be used for egress".

I would take a picture of the guard and leave.

I was always taught "minimum code" is to be enforced.


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