# Party Wall



## nitramnaed (May 7, 2020)

Hello Everyone,
Do you need a UL Floor/Ceiling (L563) rating in the cavity space of a UL rated Party Wall U305?  Specifically in the area of the airspace of the Party Wall floor framing.
IBC 2012
Occupancy R-2
Construction Type 5-A Sprinklered

Thanks, Jeff


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## classicT (May 7, 2020)

Depends on why the rated wall is necessary. Differing types of rated assemblies have differing requirements per Ch. 7 of the IBC.

I'd presume that this is just a separation wall between units, which is constructed as a Fire Partition per _IBC Section 708_. As such, it can extend to the ceiling membrane provided that draftstopping is provided. See the red highlighted sections of 78.4 below.

*708.4 Continuity*
Fire partitions shall extend from the top of the foundation or floor/ceiling assembly below to the underside of the floor or roof sheathing, slab or deck above or to the fire-resistance-rated floor/ceiling or roof/ceiling assembly above, and shall be securely attached thereto. In combustible construction where the _fire partitions _are not required to be continuous to the sheathing, deck or slab, the space between the ceiling and the sheathing, deck or slab above shall be fireblocked or draftstopped in accordance with Sections 718.2 and 718.3 at the partition line. The supporting construction shall be protected to afford the required _fire-resistance rating _of the wall supported, except for walls separating tenant spaces in _covered and open mall buildings_, walls separating _dwelling units_, walls separating _sleeping units _and _corridor _walls, in buildings of Type IIB, IIIB and VB construction.
*Exceptions:*

The wall need not be extended into the crawl space below where the floor above the crawl space has a minimum 1-hour _fire-resistance rating_.
Where the room-side fire-resistance-rated membrane of the _corridor _is carried through to the underside of the floor or roof sheathing, deck or slab of a fire-resistance-rated floor or roof above, the ceiling of the _corridor _shall be permitted to be protected by the use of ceiling materials as required for a 1-hour fire-resistance-rated floor or roof system.
Where the _corridor _ceiling is constructed as required for the _corridor _walls, the walls shall be permitted to terminate at the upper membrane of such ceiling assembly.
The fire partitions separating tenant spaces in a _covered or open mall building_, complying with Section 402.4.2.1, are not required to extend beyond the underside of a ceiling that is not part of a fire-resistance-rated assembly. A wall is not required in _attic _or ceiling spaces above tenant separation walls.
Attic fireblocking or draftstopping is not required at the partition line in Group R-2 buildings that do not exceed four _stories above grade plane_, provided the _attic _space is subdivided by draftstopping into areas not exceeding 3,000 square feet (279 m2) or above every two _dwelling units_, whichever is smaller.
Fireblocking or draftstopping is not required at the partition line in buildings equipped with an _automatic sprinkler system _installed throughout in accordance with Section 903.3.1.1 or 903.3.1.2, provided that automatic sprinklers are installed in combustible floor/ceiling and roof/ceiling spaces.


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## RLGA (May 7, 2020)

A party wall is a form of fire wall located on a lot line and does not have openings. What you're showing would not qualify as a fire wall or a party wall. A fire/party wall must be structurally independent and be continuous from the foundation to the roof, and from exterior wall to exterior wall. Thus, a floor system would not be permitted to continue through a fire/party wall.

However, if this is an occupancy separation wall, then the wall can be supported on the floor assembly, provided the floor assembly has at least the same rating as the wall. If this is for a dwelling unit or tenant separation, then a fire partition is all that is required and can be supported by the floor assembly. If the floor does not separate different dwelling units (i.e., it's a floor within a dwelling unit), then the floor is not required to have a rating.


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## e hilton (May 7, 2020)

I have never seen type C gwb.  What is it?


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## cda (May 7, 2020)

e hilton said:


> I have never seen type C gwb.  What is it?




Type c has been talked about before: but

https://lwsupply.com/blog-news/the-difference-between-type-x-and-type-c-panels/


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## RLGA (May 7, 2020)

e hilton said:


> I have never seen type C gwb.  What is it?


This is a proprietary fire-resistant-rated gypsum board. Manufacturers have their own versions of Type C gypsum board and typically have improved fire-resistance over Type X gypsum board.


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## nitramnaed (May 8, 2020)

Thanks for your responses.
In discussion with the AHJ.  He is asking for a UL rating for the gap in the wall as our Gyp-crete doesn't pass through from one apartment unit to the other.  This would require us to fill the gap with Gyp-crete which would be a logistic nightmare.  Is this gap required to be rated?  We do have a UL rated floor/ceiling system and wall system that surrounds this gap.  This is a standard detail for us that has never been questioned on other projects.

Thanks, Jeff


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## classicT (May 8, 2020)

nitramnaed said:


> Thanks for your responses.
> In discussion with the AHJ.  He is asking for a UL rating for the gap in the wall as our Gyp-crete doesn't pass through from one apartment unit to the other.  This would require us to fill the gap with Gyp-crete which would be a logistic nightmare.  Is this gap required to be rated?  We do have a UL rated floor/ceiling system and wall system that surrounds this gap.  This is a standard detail for us that has never been questioned on other projects.
> 
> Thanks, Jeff
> ...


As per my last post, it is tremendously speculative to answer your questions without knowing what type of fire-resistant wall this is. Is it a fire partition, fire barrier, or a fire wall (party wall)?


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## nitramnaed (May 8, 2020)

Ty J. said:


> As per my last post, it is tremendously speculative to answer your questions without knowing what type of fire-resistant wall this is. Is it a fire partition, fire barrier, or a fire wall (party wall)?




This is a Fire Partition.


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## classicT (May 8, 2020)

nitramnaed said:


> This is a Fire Partition.


Ok, then see my previous post.


Ty J. said:


> Depends on why the rated wall is necessary. Differing types of rated assemblies have differing requirements per Ch. 7 of the IBC.
> 
> I'd presume that this is just a separation wall between units, which is constructed as a Fire Partition per _IBC Section 708_. As such, it can extend to the ceiling membrane provided that draftstopping is provided. See the red highlighted sections of 78.4 below.
> 
> ...


As long as you have a continuous membrane, then all that is required is fire blocking. The fire partition wall is only required to extend to the rated ceiling. The plans examiner should revisit Section 708.4 and revise his/her position.


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