# please help, is this a fire code violation?



## stillmand (Apr 17, 2022)

We recently moved into a new townhouse in Ocean City, Md. It is new construction built last year. It is part of a duplex (the other connected townhouse is a mirror of ours). 

Under Ocean City, Md Code, Chapter 34, Sec. 34-44, D states:

Townhouse separation and protection.
(1) Walls separating townhouse units shall be constructed in accordance with the building code, and limited to either:
a. Two independent one-hour fire resistive wall assemblies; or
b. One common wall two-hour fire resistive wall assembly.
https://library.municode.com/md/ocean_city/codes/code_of_ordinances?nodeId=PTIICOOR_CH34FIPRPR

The blueprints call for a 2 hour fire separation wall with 2 layers of 5/8" drywall on each side of the common wall. But when we pull off an electrical outlet cover plate on either side of the common wall (our side or the neighbor's) we only see one layer of 5/8" dry wall on each side.

Is this a violation?


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## Jay Smith (Apr 17, 2022)

It’s not really a townhouse if it’s duplex. In the code, a townhouse is three or more.


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## fatboy (Apr 17, 2022)

Jay is right, if only two dwelling units, by definition, it is a duplex, not a townhouse.  As to what the plans call out, you would need to post it.


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## mtlogcabin (Apr 17, 2022)

You could have 2 one hour walls which only require one layer on each side of each individual wall. Check the total thickness of the wall(s) between the units. Or go up into the attic and see what might be there.

Our zoning requires separate lots for each unit which means there is a property line between each unit and there is a 2-hour protection between the units.


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## e hilton (Apr 18, 2022)

mtlogcabin said:


> You could have 2 one hour walls which only require one layer on each side of each individual wall.


Wouldn’t that require shaft wall studs?


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## mtlogcabin (Apr 18, 2022)

e hilton said:


> Wouldn’t that require shaft wall studs?


Not sure what you mean by "shaft wall stud"


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## Beniah Naylor (Apr 18, 2022)

I believe he means this type of product.


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## Inspector Gift (Apr 18, 2022)

TWO QUESTIONS:
1) Is there a Property Line between the dwellings?  
2) Are the dwellings protected by an Automatic Fire Suppression System?

Fire-separation in relation to the property line would require a 1-hour rated wall adjacent to the property line for *each* dwelling.   See 2018 IRC, Table R302.1(1).


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## ADAguy (Apr 18, 2022)

What year was it built?


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## mtlogcabin (Apr 18, 2022)

These are the most common assemblies that are used around here. We have seen the "shaft wall" used a couple of times which IMHO is the proper way to separate the units


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## e hilton (Apr 18, 2022)

mtlogcabin said:


> Not sure what you mean by "shaft wall stud"


If it requires 2 walls, each with a layer of 5/8” gwb on each side … how do you install the two faces that are almost touching?

I have not seen the stud shape Beniah posted, but there are metal studs for elevator shafts that allow you to install both faces of sheetrock from one side.


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## e hilton (Apr 18, 2022)

mtlogcabin said:


> . We have seen the "shaft wall" used a couple of times which IMHO is the proper way to separate the units


Yes, but in the diagram you posted, the “two hour” walls are impossible to build with wood studs, unless the second wall is built and rocked lying flat on the floor, then stood up.


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## Jay Smith (Apr 18, 2022)

The most common two-hour wood-framed separation wall I've seen is UL Design U336, which does have only one layer of wall board.


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## mtlogcabin (Apr 18, 2022)

It is the 2 layers of 1" gyp board that provides the 2 hour rating. That is why I suggested to try and figure out the width of the finished wall between the units. If 2X4 studs the wall single layer one hour wall would be 5.25 inches wide and 2X6 about 6.25 inches wide. A double wall assembly will about 10.5 inches wide






						Assembly Detail -
					






					www.usg.com


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## ICE (Apr 18, 2022)

stillmand said:


> The blueprints call for a 2 hour fire separation wall with 2 layers of 5/8" drywall on each side of the common wall. But when we pull off an electrical outlet cover plate on either side of the common wall (our side or the neighbor's) we only see one layer of 5/8" dry wall on each side.
> 
> Is this a violation?


Yes that is a violation.  No matter what type of wall has been built, it does not match the plans.  That in and of itself is a Building Code violation.  Rated walls are provided for the protection of firefighters so I would suspect that there is also a Fire Code violation.


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## redeyedfly (Apr 24, 2022)

e hilton said:


> Yes, but in the diagram you posted, the “two hour” walls are impossible to build with wood studs, unless* the second wall is built and rocked lying flat on the floor, then stood up.*


Yes, that is exactly how it is built.


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## redeyedfly (Apr 24, 2022)

e hilton said:


> I have not seen the stud shape Beniah posted, but there are metal studs for elevator shafts that allow you to install both faces of sheetrock from one side.


The stud shape posted is the one for elevators.  They're called C-T or C-H studs.  The 1" gyp fits into the T or H side of the stud and the layer(s) of 5/8" screw to the flange like any other stud.


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## my250r11 (Apr 26, 2022)

We called it shaft wall when i was wearing tools.


redeyedfly said:


> The stud shape posted is the one for elevators. They're called C-T or C-H studs. The 1" gyp fits into the T or H side of the stud and the layer(s) of 5/8" screw to the flange like any other stud.


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## mtlogcabin (Apr 26, 2022)

Example of a shaft wall separation

Attic separation 


Unit separation


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## mark handler (Apr 26, 2022)

Inspector Gift said:


> TWO QUESTIONS:
> 1) Is there a Property Line between the dwellings?
> 2) Are the dwellings protected by an Automatic Fire Suppression System?
> 
> Fire-separation in relation to the property line would require a 1-hour rated wall adjacent to the property line for *each* dwelling.   See 2018 IRC, Table R302.1(1).


But it was altered by the Muni-code


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## mark handler (Apr 26, 2022)

If it was permitted as duplex units, according to Municode, does not require two hour walls
If it was permitted as a Townhouse, according to Municode, it does require a two hour walls.

A change "may have" been made during construction reclassifying it as a duplex. See if there were any changes made to the classification prior to or during construction


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## redeyedfly (Apr 26, 2022)

my250r11 said:


> We called it shaft wall when i was wearing tools.


The field tends to call them shaftwalls, DP offices tends to call them C-H or shaftwall depending on how often they get out on site.


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