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Attic Area Limitation - Fire suppression system required

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matatat

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New York City
Hello, I'm working on a project under the NJ IRC 2018. It's a historic farmhouse, and it has a below grade basement, two full stories, and a full attic space over the entire footprint. The steep roof pitch allows for almost total occupancy of the attic, with the exception of knee walls along the sides at the rafter bearing locations.The existing attic space is partially finished currently, as a part of the renovation we would like to completely finish it. No sleeping rooms, just nice storage, a little work space

We received a rejection from the local building department stating the following:

"N.J.A.C. 5:23-6.8 - Height + Area / NJ IRC 2018 - R 300.1 No habitable attic exceeds 1/3 floor below, so third floor occupancy requires residential fire suppression per R300.2 VB construction"

I have looked up the codes cited here, and it says nothing about the attic area limitation to 1/3 of the floor below. I have also never heard this requirement before, and can't find it anywhere in the code (I'm a registered architect in NJ, NY, MA, SC, and TN). Am I missing something here? And are we really required to add a sprinkler system to an existing habitable attic space? That seems like an unnecessary burden to place on the new homeowner, because the space was already considered "habitable" by code definition. Any thoughts or guidance would be appreciated! If this 1/3 area requirement exists in the code, could anyone point me to the exact citation? Thanks in advance!
 
matatat said:
Hello, I'm working on a project under the NJ IRC 2018. It's a historic farmhouse, and it has a below grade basement, two full stories, and a full attic space over the entire footprint. The steep roof pitch allows for almost total occupancy of the attic, with the exception of knee walls along the sides at the rafter bearing locations.The existing attic space is partially finished currently, as a part of the renovation we would like to completely finish it. No sleeping rooms, just nice storage, a little work space

We received a rejection from the local building department stating the following:

"N.J.A.C. 5:23-6.8 - Height + Area / NJ IRC 2018 - R 300.1 No habitable attic exceeds 1/3 floor below, so third floor occupancy requires residential fire suppression per R300.2 VB construction"

I have looked up the codes cited here, and it says nothing about the attic area limitation to 1/3 of the floor below. I have also never heard this requirement before, and can't find it anywhere in the code (I'm a registered architect in NJ, NY, MA, SC, and TN). Am I missing something here? And are we really required to add a sprinkler system to an existing habitable attic space? That seems like an unnecessary burden to place on the new homeowner, because the space was already considered "habitable" by code definition. Any thoughts or guidance would be appreciated! If this 1/3 area requirement exists in the code, could anyone point me to the exact citation? Thanks in advance!
Click to expand...




Did you find this;

"N.J.A.C. 5:23-6.8



Is the owner going to occupy the entire house ?? Or rent some areas out?
 
R300.1 General
Buildings of VB, unprotected wood-framed construction, as that term is defined in Section 602 of the building subcode, shall be not more than two stories, not more than 35 feet in height (10 668 mm), and not more than 4,800 square feet in area per floor. For the purpose of applying this subsection, a habitable attic shall not constitute a story in a two-story dwelling.

R300.2 Increases in Height
The building shall be not more than three stories and not more than 55 feet (16 764 mm) in height where the building is equipped throughout with an automatic sprinkler system installed in accordance with the National Fire Protection Association (NFPA) Standard 13D or Section P2904.​

Looks like you must have sprinklers to be (3) stories.
 
Ty J. said:
R300.1 General
Buildings of VB, unprotected wood-framed construction, as that term is defined in Section 602 of the building subcode, shall be not more than two stories, not more than 35 feet in height (10 668 mm), and not more than 4,800 square feet in area per floor. For the purpose of applying this subsection, a habitable attic shall not constitute a story in a two-story dwelling.

R300.2 Increases in Height
The building shall be not more than three stories and not more than 55 feet (16 764 mm) in height where the building is equipped throughout with an automatic sprinkler system installed in accordance with the National Fire Protection Association (NFPA) Standard 13D or Section P2904.​

Looks like you must have sprinklers to be (3) stories.
Click to expand...

Thanks for the code reference. My interpretation of that is that a "habitable attic" is allowed, and is not considered a story counting towards the two story maximum. Our habitable attic meets all the requirements of the definition per R202

[RB] ATTIC, HABITABLE. A finished or unfinished area, not considered a story, complying with all of the following requirement:

1. The occupiable floor area is not less than 70 sf., in accordance with Section R304.

2. The occupiable floor area has a ceiling height in accordance with Section R305.

3. The occupiable space is enclosed by the roof assembly above, knee walls (if applicable) on the sides and the floor-ceiling assembly below.
 
Do you have a link to


"N.J.A.C. 5:23-6.8 - Height + Area / NJ IRC 2018 - R 300.1
 
cda said:
Do you have a link to


"N.J.A.C. 5:23-6.8 - Height + Area / NJ IRC 2018 - R 300.1
Click to expand...

This is the link to the IRC:
https://up.codes/viewer/new_jersey/irc-2018/chapter/3/building-planning#3

Here is a link the NJAC (slightly outdated version, I believe):
https://www.state.nj.us/dca/divisions/codes/codreg/pdf_regs_former/njac_5_23_6_Nov_5_07.pdf

The code section called out in the NJAC seems to be referencing materials and methods? I must be missing something here though....
 
cda said:
https://up.codes/viewer/new_jersey/irc-2018/chapter/3/building-planning#3


Are they say you are increasing the height???

If so looks like sprinkler is required



Sounds like you need another set down with reviewer and more than likely their boss

To clarify everything
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Hmmm...we aren't increasing the height - the space is existing right now. It already has a full staircase up to it (not a pull-down attic access). It is fully habitable right now, it is just not finished (no sheetrock, lighting, electrical, etc.). We wanted to finish it.

It does seem like this needs to be discussed in person with the AHJ. I can't understand why we would have to add sprinklers. It is already existing, accessible, and habitable. In fact, finishing it would make it even more safe, rather than a full story with exposed rafters, we would be encasing with sheetrock.
 
Just found it! Posting here for future and others' reference. I must have been looking at a different state's IRC amendments, or an outdated version of the IRC when I looked up the definition:

https://up.codes/viewer/new_jersey/irc-2018/chapter/2/definitions#2

ATTIC, HABITABLE. An attic that has a stairway as a means of access and egress and in which the ceiling area at a height of 7 feet (2134 mm) above the attic floor is not more than one-third the area of the next floor below.

Thanks all for helping me think through this!
 
Ty J. said:
R300.1 General
Buildings of VB, unprotected wood-framed construction, as that term is defined in Section 602 of the building subcode, shall be not more than two stories, not more than 35 feet in height (10 668 mm), and not more than 4,800 square feet in area per floor. For the purpose of applying this subsection, a habitable attic shall not constitute a story in a two-story dwelling.

R300.2 Increases in Height
The building shall be not more than three stories and not more than 55 feet (16 764 mm) in height where the building is equipped throughout with an automatic sprinkler system installed in accordance with the National Fire Protection Association (NFPA) Standard 13D or Section P2904.​

Looks like you must have sprinklers to be (3) stories.
Click to expand...



“”For the purpose of applying this subsection, a habitable attic shall not constitute a story in a two-story dwelling.“””


So is he 2 or 3 story??

I get lost on this code language sometimes
 
matatat said:
Just found it! Posting here for future and others' reference. I must have been looking at a different state's IRC amendments, or an outdated version of the IRC when I looked up the definition:

https://up.codes/viewer/new_jersey/irc-2018/chapter/2/definitions#2

ATTIC, HABITABLE. An attic that has a stairway as a means of access and egress and in which the ceiling area at a height of 7 feet (2134 mm) above the attic floor is not more than one-third the area of the next floor below.

Thanks all for helping me think through this!
Click to expand...



Yep all those hidden codes,, anyway now you can take back all those nice things you said about the plan reviewer
 
cda said:
“”For the purpose of applying this subsection, a habitable attic shall not constitute a story in a two-story dwelling.“””


So is he 2 or 3 story??

I get lost on this code language sometimes
Click to expand...

I believe that because our attic area is more than 1/3 of the footprint below, it is actually considered a third floor, thus requiring a sprinkler system
 
matatat said:
I believe that because our attic area is more than 1/3 of the footprint below, it is actually considered a third floor, thus requiring a sprinkler system
Click to expand...

it will be a safer world!!


Keep on coming back, And this is a self supporting site,,, so join up as a Sawhorse and help us!!!

Besides, that what this answer cost you, you saved a lot by not going to a consultant.
 
I see this post is old, but I have to correct the record.
In NJ renovations are almost always covered by a different section of the code: The rehabilitation subcode.

NJ Department of Community Affairs

background and guidance of rehab subcode
www.nj.gov

To be fair this is not well known, and most architect's attempt to always design to new construction code/IRC since it is simpler, but in this particular case in order to avoid the addition of a sprinkler to an existing attic it would have behooved the design professional to research the correct code section.
It may very well be that a sprinkler would be required even in the rehab subcode- I have not looked into this in particular- but it is an error not to check when relevant.
 
Jay F said:
I see this post is old, but I have to correct the record.
In NJ renovations are almost always covered by a different section of the code: The rehabilitation subcode.

NJ Department of Community Affairs

background and guidance of rehab subcode
www.nj.gov

To be fair this is not well known, and most architect's attempt to always design to new construction code/IRC since it is simpler, but in this particular case in order to avoid the addition of a sprinkler to an existing attic it would have behooved the design professional to research the correct code section.
It may very well be that a sprinkler would be required even in the rehab subcode- I have not looked into this in particular- but it is an error not to check when relevant.
Click to expand...

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