R-2 Rooftop Patio and Number of Stories

[texasbo]

Yeah, just because you don't make up codes like I do, it doesn't exist.

Fixed it for you

Sorry brudgers. Your hillbilly logic may work for you, but I'm not buying it. But you just keep on calculating the area of the roof as part of the building area. I'm sure you look at it as a "safety factor" to compensate for your crappy design.

And you just keep calling an open roof a story, because somewhere, way up there, the sky must have a roof, huh?

 

[Papio Bldg Dept]

See section 506.4 Re: The original post

The building described has more than one story above grade plane, therefore total allowable area for the building is determined by multiplying the number of stories in Table 503 by the allowable area of each story in table 503 (as the general case). This would allow an R2 occupancy on the roof but the occupied area of the roof would be counted against the total allowable area of the building under section 506.4.

Example:

Type IIIA Occupancy R2 would have a total allowable area of 24k sf x 4 stories = 96k sf.

If the rooftop area was 16k sf, then the maximum aggregate area of the four stories would be 80k sf with no story being more than 24k sf.

However, the proposed rooftop use is an assembly occupancy and would require a construction type which allows a four story assembly occupancy and would count against the total allowable area of the building under 506.4.

Thanks Brudgers. That is very helpful example and I agree with your logic, however I keep getting hung up on the commentary for 502, Area, Building. "A building area is the 'footprint' of the building; that is, the area measured within the perimeter formed by the inside surface of the exterior walls, which excludes spaces that are inside this perimeter and open to the outside atmosphere at the top...When a portion of the building has no exterior walls, the area regulated by Chapter 5 is defined by the projection of the roof or floor above."

It is my understanding that an open court in the middle of the building would not be included in 506.4 calculations, even though we assign it an occupancy. A 3-story, Group R-2, V-B building with a 10,000sf footprint at the first story, each additional story is 7,000 sf with the 3,000sf central courtyard A-3 on the first level. This A-3 occupancy would not be calculated as part of the allowable area per Table 503, and would be compliant. It is this type of logic that makes it more difficult for me to clarify the difference between an open court, whether on the first level or 4th level as being restricted by Table 503.

Is it just me or is this building design not clearly defined by ICC? As I see it, both have logical perspectives, all hinged on the application of Table 503 to the open-to-above occupancies that may be found in a court or on a roof. So now we have all figured out what we are dealing with, are we not now just discussing/haggling over price, in this case the life safety cost of placing an occupancy inside a courtyard or up on a roof?

 

[Papio Bldg Dept]

Fixed it for youSorry brudgers. Your hillbilly logic may work for you, but I'm not buying it. But you just keep on calculating the area of the roof as part of the building area. I'm sure you look at it as a "safety factor" to compensate for your crappy design.

And you just keep calling an open roof a story, because somewhere, way up there, the sky must have a roof, huh?

OT. I understand that neither of you is going to ask each other to the Christmas Ball this year, but there is no need to question each other's comprehension or design talents when discussing Chapter 5 Allowable Area and Height calculations. If anyone's comprehension and design talents should be questioned, I believe it should be ICC's. Especially when we are haggling over allowable areas that were defined by a survey of California Building Departments over twenty years ago (granted modifications have been made, but to my knowledge there has never been one offering of scientific research to back up these heights and areas. We have simply accepted them either on blind faith as reasonable, or as some reaction to a life-safety tragedy). The Palaeartic Forum is better place to be silly.

 

[texasbo]

OT. I understand that neither of you is going to ask each other to the Christmas Ball this year, but there is no need to question each other's comprehension or design talents when discussing Chapter 5 Allowable Area and Height calculations. If anyone's comprehension and design talents should be questioned, I believe it should be ICC's. Especially when we are haggling over allowable areas that were defined by a survey of California Building Departments over twenty years ago (granted modifications have been made, but to my knowledge there has never been one offering of scientific research to back up these heights and areas. We have simply accepted them either on blind faith as reasonable, or as some reaction to a life-safety tragedy). The Palaeartic Forum is better place to be silly.

You don't understand. EVERY SINGLE TIME he shows his a$$, he's going to get it right back in his face. Period.

More importantly, you missed the real point of my post; a roof is not a story, and allowable area and height are calculated by story. That's a definition, not some cornpone, made up, "because I want it to" backwoods opinion.

 

[Papio Bldg Dept]

The use on the roof and the height limits based on construction type should determine if the use is permitted.Example a 4 story V-B hotel should not be permitted to have a assembly use on it as the use is more than 3 floors in height. change the construction type and it will work.

Could the same hotel have a heliport on the roof, or a small dining area with less an OL of less than 50?

I agree, Construction Type changes would solve the issue and make for a clearly compliant design no matter how you use Table 503, but your question brings up an interesting point. How should we address open air occupancies with no exterior walls or floor/roof above? Interior Courtyards aren't applicable to Table 503 limitations, no matter what level they are on, why should roof tops be any different? There is logic to be comprehended on both sides of the allowable areas ceiling/roof/wall based upon the way the ICC has defined their codes and commentary.

 

[Papio Bldg Dept]

You don't understand. EVERY SINGLE TIME he shows his a$$, he's going to get it right back in his face. Period.More importantly, you missed the real point of my post; a roof is not a story, and allowable area and height are calculated by story. That's a definition, not some cornpone, made up, "because I want it to" backwoods opinion.

I agree, that a roof is not a story. I also agree that the roof needs to have an occupancy assigned if accessible. I haven't seen brudgers reference a Farmer's Almanac yet, so I have no comment on your feelings towards his opinions. The commentary, however, confuses things even more by referring to stories as levels (another ICC brilliance). How do you define level?

 

[texasbo]

I agree, that a roof is not a story. I also agree that the roof needs to have an occupancy assigned if accessible. I haven't seen brudgers reference a Farmer's Almanac yet, so I have no comment on your feelings towards his opinions. The commentary, however, confuses things even more by referring to stories as levels (another ICC brilliance). How do you define level?

Well, I can only hope he is better with the Farmers Almanac than he is with the code.

I would steer clear of the commentary. Probably the only thing that we both agree on is that the commentary is just somebody else's opinion. I'm also in complete agreement that the roof needs an occupancy, and that it must, by code, be exited appropriately. There is absolutely no controversy there. I don't think, anyway.

 

[brudgers]

Thanks Brudgers. That is very helpful example and I agree with your logic, however I keep getting hung up on the commentary for 502, Area, Building. "A building area is the 'footprint' of the building; that is, the area measured within the perimeter formed by the inside surface of the exterior walls, which excludes spaces that are inside this perimeter and open to the outside atmosphere at the top...When a portion of the building has no exterior walls, the area regulated by Chapter 5 is defined by the projection of the roof or floor above." It is my understanding that an open court in the middle of the building would not be included in 506.4 calculations, even though we assign it an occupancy. A 3-story, Group R-2, V-B building with a 10,000sf footprint at the first story, each additional story is 7,000 sf with the 3,000sf central courtyard A-3 on the first level. This A-3 occupancy would not be calculated as part of the allowable area per Table 503, and would be compliant. It is this type of logic that makes it more difficult for me to clarify the difference between an open court, whether on the first level or 4th level as being restricted by Table 503. Is it just me or is this building design not clearly defined by ICC? As I see it, both have logical perspectives, all hinged on the application of Table 503 to the open-to-above occupancies that may be found in a court or on a roof. So now we have all figured out what we are dealing with, are we not now just discussing/haggling over price, in this case the life safety cost of placing an occupancy inside a courtyard or up on a roof?

Section 506.4 only applies to buildings with more than one story above grade - so the courtyard is not an apples to apples comparison. Not to mention that courtyards at grade can serve uniquely as life safety enhancements.

Finally, the commentary is not the code and is written by someone under a contract to say something about everything and nothing about specific buildings.

And as your instructor demonstrates, it is easy for someone at the ICC to be completely off base on a code interpretation.

 

[brudgers]

OT. I understand that neither of you is going to ask each other to the Christmas Ball this year, but there is no need to question each other's comprehension or design talents when discussing Chapter 5 Allowable Area and Height calculations. If anyone's comprehension and design talents should be questioned, I believe it should be ICC's. Especially when we are haggling over allowable areas that were defined by a survey of California Building Departments over twenty years ago (granted modifications have been made, but to my knowledge there has never been one offering of scientific research to back up these heights and areas. We have simply accepted them either on blind faith as reasonable, or as some reaction to a life-safety tragedy). The Palaeartic Forum is better place to be silly.

You can't keep a Building Official/Zoning Official from acting like one. Even by taking away their blue jumper and red shoes.

 

[brudgers]

You don't understand. EVERY SINGLE TIME he shows his a$$, he's going to get it right back in his face. Period. More importantly, you missed the real point of my post; a roof is not a story, and allowable area and height are calculated by story. That's a definition, not some cornpone, made up, "because I want it to" backwoods opinion.

You can lead a Building Official/Zoning Official to the correct interpretation. But you can't make 'em think.

The orange hair is too distracting.

 

[texasbo]

You can lead a Building Official/Zoning Official to the correct interpretation. But you can't make 'em think.

The orange hair is too distracting.

Brudgers, you do realize that a codebook can be used for things other than sitting on in order to reach your drafting board, don't you?

 

[Papio Bldg Dept]

You can't keep a Building Official/Zoning Official from acting like one. Even by taking away their blue jumper and red shoes.

You are going to take away my blue jumper and red shoes? What will I wear to the Christmas Ball?

 

[Papio Bldg Dept]

Section 506.4 only applies to buildings with more than one story above grade - so the courtyard is not an apples to apples comparison. Not to mention that courtyards at grade can serve uniquely as life safety enhancements.

Okay, let's make it macintosh's to gala's then and move the courtyard up a level or two. Then what happens? Now we have to sprinkle the building (but not the courtyard), to get an A-3 above the first floor? Or is a courtyard at the second level still exempt from 503? I don't agree that interior courtyards at grade level are inherently safer. Can they be life safety enhancements? Yes, but that is not a given. A 50ft x 50ft will not give you a compliant safe dispersal area as required by 1024.6. Keep leading me, I am trying to think this through, blue jumper and red shoes or not.

Thank you again for your efforts, I do appreciate it.

 

[brudgers]

Okay, let's make it macintosh's to gala's then and move the courtyard up a level or two. Then what happens? Now we have to sprinkle the building (but not the courtyard), to get an A-3 above the first floor? Or is a courtyard at the second level still exempt from 503? I don't agree that interior courtyards at grade level are inherently safer. Can they be life safety enhancements? Yes, but that is not a given. A 50ft x 50ft will not give you a compliant safe dispersal area as required by 1024.6. Keep leading me, I am trying to think this through, blue jumper and red shoes or not. Thank you again for your efforts, I do appreciate it.

1. I said "can serve" but did not mean that they will always do so - only that there are entirely different criteria for evaluating them which interfere with your comparison. 2. Thinking out loud - If it's at the second level and a courtyard, would it not be the case that it is surrounded by exterior walls? I.e, your situation could still be interpreted as significantly different from a rooftop use. See definition of "court."

3. What is muddying the analysis this is that there are two separate issues, rooftop use, mixed occupancy, and no actual plan to analyze. There are three issues muddying the analysis....

4. Table 503 is explicit - "Height limitations shown as stories and feet above grade plane."

 

[texasbo]

3. What is muddying the analysis this is that there are two separate issues, rooftop use, mixed occupancy, and no actual plan to analyze. There are three issues muddying the analysis....

4. Table 503 is explicit - "Height limitations shown as stories and feet above grade plane."

3. Two issues, three issues, whatever it takes. I say there are four issues muddying the analysis...

4. OK; you finally read the code, so maybe you can discuss this a little more intelligently . Now for the big questions: are you backing out of your contention that an open roof is a story, and if so, if it is an occupancy that is not allowed as a 4th story, do you agree that it complies with the code, IF it is below the allowable height in feet?

 

[Papio Bldg Dept]

1. I said "can serve" but did not mean that they will always do so - only that there are entirely different criteria for evaluating them which interfere with your comparison.

2. Thinking out loud - If it's at the second level and a courtyard, would it not be the case that it is surrounded by exterior walls? I.e, your situation could still be interpreted as significantly different from a rooftop use. See definition of "court."

Noted, however if we move the courtyard to the second floor and towards the exterior of the building envelope, then we might be talking apples to apples, or maybe we are talking about coconuts.

3. What is muddying the analysis this is that there are two separate issues, rooftop use, mixed occupancy, and no actual plan to analyze. There are three issues muddying the analysis....

Agreed, an example/plan would greatly help clear up the discussion and give us something tangible to analyze.

4. Table 503 is explicit - "Height limitations shown as stories and feet above grade plane."

Table 503 also explicitly notes that area limitations are to be determined by the definition of "Area, building," per story. Now we are back to discussing an area not circumscribed (surrounded) by exterior walls and with no floor or roof above, which shall not be included in the building area. Defining Height, story, furthers my misunderstanding in that this court can not be described by the definition provided. If it is not to be defined by the building area, or by height story (504 reiterates this, even accounting for penthouses, which are also given an occupancy, and further detailed in 504.3 as not for habitation), then all I am left to understand is that it is only defined by an occupancy group for Structural and MOE purposes.

Thusly, thoust is confuddled! Have a great weekend.

 

[Papio Bldg Dept]

is an occupancy that is not allowed as a 4th story, do you agree that it complies with the code, IF it is below the allowable height in feet?

base elevation/first finished floor = 100'-0"

second floor finished elevation = 112'-0"

third floor finished elevation = 124'-0"

roof deck/courtyard with pool and grill finished floor elevation = 136'-0"

top of parapet = 140'-0"

A feasible discussion point for an 3 story, V-B construction R-occupancy with A3 on the roof...and muddy waters.

 

[texasbo]

Papio, to get apples to apples, lets stay with the OP R2, VA - is that ok?

In that case, I would say yes, A3 on roof complies. It isn't a story above 3 (with sprinklers), and it doesn't bust height at 36'-0" above grade.

 

[brudgers]

Noted, however if we move the courtyard to the second floor and towards the exterior of the building envelope, then we might be talking apples to apples, or maybe we are talking about coconuts. Agreed, an example/plan would greatly help clear up the discussion and give us something tangible to analyze. Table 503 also explicitly notes that area limitations are to be determined by the definition of "Area, building," per story. Now we are back to discussing an area not circumscribed (surrounded) by exterior walls and with no floor or roof above, which shall not be included in the building area. Defining Height, story, furthers my misunderstanding in that this court can not be described by the definition provided. If it is not to be defined by the building area, or by height story (504 reiterates this, even accounting for penthouses, which are also given an occupancy, and further detailed in 504.3 as not for habitation), then all I am left to understand is that it is only defined by an occupancy group for Structural and MOE purposes. Thusly, thoust is confuddled! Have a great weekend.

The surface of the roof is "within the horizontal projection of the roof." "Above" is a condition placed on floors - because the horizontal projection of floors both above and below would mean that the area of every floor was equal to that of the largest floor. And please, I beg of you - point to the portion of the Building Area definition which mentions stories.

 

[brudgers]

3. Two issues, three issues, whatever it takes. I say there are four issues muddying the analysis... 4. OK; you finally read the code, so maybe you can discuss this a little more intelligently . Now for the big questions: are you backing out of your contention that an open roof is a story, and if so, if it is an occupancy that is not allowed as a 4th story, do you agree that it complies with the code, IF it is below the allowable height in feet?

I never said the roof was a story. http://www.inspectpa.com/forum/showthread.php?5199-R-2-Rooftop-Patio-and-Number-of-Stories&p=52796&viewfull=1#post52796

 

[brudgers]

base elevation/first finished floor = 100'-0" second floor finished elevation = 112'-0" third floor finished elevation = 124'-0" roof deck/courtyard with pool and grill finished floor elevation = 136'-0" top of parapet = 140'-0" A feasible discussion point for an 3 story, V-B construction R-occupancy with A3 on the roof...and muddy waters.

No because the A3 occupancy would be more than than two stories above grade because it is above the third story, even though the roof is not a story.

 

[texasbo]

The surface of the roof is "within the horizontal projection of the roof."

Brudgers, may I suggest that you stop posting on this board within 2 hours after you begin drinking? With that ridiculous postulate, every building would be reduced in allowable area by the square footage of its roof. You are really desperate and reaching for straws on this one; for the love of God, stop before you embarrass yourself further.

 

[texasbo]

And please, I beg of you - point to the portion of the Building Area definition which mentions stories.

Table 503, header, 2006 IBC: "Area limitations as determined by the definition of "Area, building", PER STORY.

 

[texasbo]

No because the A3 occupancy would be more than than two stories above grade because it is above the third story, even though the roof is not a story.

Table 503, Header, "Height limitations SHOWN AS STORIES..."