# 2-hour seperation to save a 155 year old tin ceiling



## Resident Artist (Feb 24, 2021)

We recently purchased a mixed use commercial building on a popular tourist strip, a three-story brownstone style build in 1855.

The main level retail will be our gallery/showroom, and we're converting the upper two floors into our private residence. 

In the main floor galley it has the original 1855 tin ceiling. We need to make it a 2-hour fire separation. The tin in attached to 1/2" plaster and lath on 2x14 joists. The floor above is the original floorboards. 

We had one person tell us we would need to remove the tin tiles and add dry-wall, and another suggested we could build up the floor above. The city says they'll approve whatever a certified expert says gives us a 2-hour fire separation.  

The original plan is to add 23/32" OSB sub-floor, electric radiant heat floor system, 1/2" of quickcrete over that, and 3/4" hardwood flooring.

This is a logn way of asking if we can achieve a 2-hour rating by adding material to the top of the separation rather than the bottom?


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## cda (Feb 24, 2021)

Welcome.

Give it a few days, for answers


Not my area, but I think you can add the two hour wall on top, may be a little problem to do

Who is helping you with code questions/ design??

Does the building have a fire sprinkler system??

If not are being asked to install one?


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## cda (Feb 24, 2021)

How many square feet is each floor

Wonder if you could be a live work per IBC


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## steveray (Feb 25, 2021)

Hire a designer or code consultant....doesn't seem right.would they accept sprinklers as an alternative?


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## fatboy (Feb 25, 2021)

Agree with steveray, save yourself the time, money and sanity, and hire a RDP as the City has stated that is what they will accept. 

"The city says they'll approve whatever a certified expert says gives us a 2-hour fire separation."

Trust us, you can play the "what if" game forever, but that does not get your project underway.


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## Resident Artist (Feb 25, 2021)

More details:

The floors are 15' x 57', so just under 900 sq/ft. The top two floors are being opened to each other for an open loft floor plan for our personal residence, so as per the city inspector the 3rd floor doesn't enter into this.

We've 100% gutted the middle floor, so it's currently wide open, side to side and front to back. 

What is an "RDP?" We did hire a local architect who put together a detailed multi-page score/rating report, and we fell just under the score we needed to not have to add a sprinkler system. Making the ceiling/floor between the main floor gallery and the residence 2-hour rated puts us above this score minimum.

Sprinkler is an option, but for both esthetics and budget we'd rather exhaust our options for the 2-hour separation first, especially so considering how many layers are already being added to the top.


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## tmurray (Feb 25, 2021)

Your architect is the one who should be telling you how to get the rating. 

I would not accept rating the ceiling from above. Building codes typically requires ratings of ceilings to be from below (the fire rated sheetrock would have to be below the joists).


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## cda (Feb 25, 2021)

Resident Artist said:


> More details:
> 
> The floors are 15' x 57', so just under 900 sq/ft. The top two floors are being opened to each other for an open loft floor plan for our personal residence, so as per the city inspector the 3rd floor doesn't enter into this.
> 
> ...




mid your Architect has a code book

More than likely a version of the international building code 

Have them look at chapter 4 got Live/work section

See if that saves you some money


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## Inspector Gift (Feb 25, 2021)

"RDP" = Registered Design Professional (i.e., Architect or Engineer)


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## classicT (Feb 25, 2021)

Generally speaking, your issue will be that whatever you add to the top side of the existing floor/ceiling assembly to achieve the required 2-hr separation is going to be supported by that existing floor/ceiling assembly.

This means if the fire burns the existing floor out, whatever fire separation you added above, will just fall. Thus, you did not achieve the 2-hr separation.

Sorry to be the bearer of bad news, but the fire resistive almost always have to go on the underside of the floor (ceiling side).

Suggest that you start looking into how to salvage the existing tin roof, and then have it reinstalled.


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## steveray (Feb 25, 2021)

Intumescent paint?


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## classicT (Feb 25, 2021)

steveray said:


> Intumescent paint?


Typically, intumescent paint protects an individual component and does not create a horizontal assembly.

As an example, you can coat a steal beam with intumescent paint to protect the beam. That beam could then support a horizontal assembly.


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## redeyedfly (Feb 25, 2021)

Considering the small size of the spaces it seems you could design it as nonseparated occupancies.  Ask your architect to review IBC 508.3.

I've never heard of scoring for sprinklers.  They're either required for the occupancy or you're adding them to reduce other fire protective requirements.


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## jeffc (Feb 25, 2021)

I would hire a Fire Protection Engineer. More than likely, this will be a performance design that substitutes an alternative, but equivalent, means of protection. For example, install combination, or mix of, a sidewall fire sprinkler system below, smoke detection above and below the ceiling, enhanced exiting above...


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## cda (Feb 25, 2021)

Live work help any???   Chapter 4


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## mtlogcabin (Feb 25, 2021)

Resident Artist said:


> The tin in attached to 1/2" plaster and lath on 2x14 joists. The floor above is the original floorboards.


Ask your architect to look at this section. If you sprinkle the entire building then you reduce the fire separation rating from 2 hours to 1 hour. The exception below may let you use the existing construction to meet that one hour requirement if your architect will verify that is what is there.


2018  International Existing Building Code (IEBC)
1011.5.3 Fire barriers.
Where a change of occupancy classification is made to a higher-hazard category as shown in Table 1011.5, fire barriers in separated mixed use buildings shall comply with the fire-resistance requirements of the International Building Code.

*Exception: Where the fire barriers are required to have a 1-hour fire-resistance rating, existing wood lath and plaster in good condition or existing 1/2-inch-thick (12.7 mm) gypsum wallboard shall be permitted.*

2018 IBC
711.2.3 Supporting construction.
The supporting construction shall be protected to afford the required fire-resistance rating of the horizontal assembly supported. 

*Exception: In buildings of Type IIB, IIIB or VB construction, the construction supporting the horizontal assembly is not required to be fire-resistance rated at the following:*

1.    Horizontal assemblies at the separations of incidental uses as specified by Table 509 provided that the required fire-resistance rating does not exceed 1 hour.

*2.    Horizontal assemblies at the separations of dwelling units and sleeping units as required by Section 420.3.*

3.    Horizontal assemblies at smoke barriers constructed in accordance with Section 709.


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## Resident Artist (Feb 25, 2021)

redeyedfly said:


> They're either required for the occupancy or you're adding them to reduce other fire protective requirements.


I think this is closer to what I meant to say. I only remember that it was a longer questionnaire/list of specifics/conditions that included "sprinklers?" (that was a 'no' on the list) and we had to be above a set cumulative number for occupancy. A "Sprinklers; Yes" would put us above this number, as well as a few other changes on the list (most couldn't be changed), and a 2-hour separation was one of them (currently rated a 1-hour separation).


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## fatboy (Feb 25, 2021)

When Resident Artist spoke of the "scoring", my thoughts went to the International Existing Building Code, there is a path for performance of existing buildings.


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## Resident Artist (Feb 25, 2021)

fatboy said:


> When Resident Artist spoke of the "scoring", my thoughts went to the International Existing Building Code, there is a path for performance of existing buildings.
> 
> View attachment 7530


So I had to look it up, it was called: "Performance Compliance Evaluation IEBC Section 1401.5" checking for "Fire Safety", "Means of Egress," and "General Safety,"  and at the end of the survey it says, "A negative score fails."


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## Resident Artist (Feb 25, 2021)

#16: Mixed Occupancy Value is what hurts the score. Adding a 2-hour separation adds 10 points.


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## fatboy (Feb 25, 2021)

Resident Artist said:


> So I had to look it up, it was called: "Performance Compliance Evaluation IEBC Section 1401.5" checking for "Fire Safety", "Means of Egress," and "General Safety,"  and at the end of the survey it says, "A negative score fails."


 What code cycle is/are he/they using? In the 2018, Chapter 14 is Moved/Relocated Buildings.


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## cda (Feb 25, 2021)

Anyone want to say if live work helps???

IBC

*419.2 Occupancies

Live/work units shall be classified as a Group R-2 occupancy. Separation requirements found in Sections 420 and 508 shall not apply within the live/work unit where the live/work unit is in compliance with Section 419. Nonresidential uses that would otherwise be classified as either a Group H or S occupancy shall not be permitted in a live/work unit. 
Exception: Storage shall be permitted in the live/work unit provided the aggregate area of storage in the nonresidential portion of the live/work unit shall be limited to 10 percent of the space dedicated to nonresidential activities.*


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## Resident Artist (Feb 25, 2021)

fatboy said:


> What code cycle is/are he/they using? In the 2018, Chapter 14 is Moved/Relocated Buildings.


It doesn't say. I only see, "Performance Compliance Evaluation IEBC Section 1401.5" on the top of this.


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## jar546 (Feb 25, 2021)

I had this situation and the RDP found a product that was spray on which required a special inspection for thickness.  With RDP and special inspections, they were able to protect the metal ceiling from being removed.  Chapter 7 had to be utilized for the balance of the horizontal separation requirements.


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## fatboy (Feb 26, 2021)

"Anyone want to say if live work helps???

cda,

Yes, it appears it could work. They would still have to install a sprinkler system, which they were trying to avoid. But, yes, they could dodge the separation requirement though.

_                  [F] 419.5 Fire protection. The live/work unit shall be provided with a monitored fire alarm system where required by Section 907.2.9 and an automatic                         sprinkler system in accordance with Section 903.2.8._

They meet the square foot requirements for the size overall, and the size of the business to residential ratio.

_                 419.1.1 Limitations. All of the following shall apply to live/work areas: 
                          1. The live/work unit is permitted to be not greater than 3,000 square feet (279 m2 ) in area. 
                          2. The nonresidential area is permitted to be not more than 50 percent of the area of each live/work unit. 
                          3. The nonresidential area function shall be limited to the first or main floor only of the live/work unit. 
                          4. Not more than five nonresidential workers or employees are allowed to occupy the nonresidential area at any one time._

Installing a fire sprinkler system in the walls would be an option to avoid penetrating the historic tin ceiling.

BTW, the analysis must have been using the 2015,   Chapter's 13 and 14 were reversed.


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## Resident Artist (Feb 26, 2021)

jar546 said:


> I had this situation and the RDP found a product that was spray on which required a special inspection for thickness.


Do you recall what the product name was?


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## jar546 (Feb 27, 2021)

Resident Artist said:


> Do you recall what the product name was?


No it was about 10 years ago and I don't live in that state anymore


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## Robert (Mar 3, 2021)

Don't forget acoustic separation between residential and commercial. Most times this can only be achieved with RC channels on the ceiling (or a generous topping slab above). If this was analyzed as non-separated (as Redeyefly suggested), would the B occupancy be the most hazardous or the R? Also, does the building have any historical designation? If so, the historical building code has exceptions to help preserve original items.


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## Resident Artist (Mar 4, 2021)

I want to thank everyone for the input. We're getting quotes now for a sprinkler system. The city ran a dedicated fire-water line in the street 15 years ago, and there's a valve four our building five feet from the front of the building. We just have to bust open the sidewalk. Sidewall sprinkler isn't an option as we're in a row of 1855 buildings.

Acoustics shouldn't be a problem (I didn't see or hear of any specific requirement from the architect or city). Above the tin ceiling the floor assemble will be the original floor-boards, 23/32" plywood subfloor, 1/2" quickcrete over the electric radiant floor system, and then 3/4" hardwood.


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## cda (Mar 4, 2021)

Resident Artist said:


> I want to thank everyone for the input. We're getting quotes now for a sprinkler system. The city ran a dedicated fire-water line in the street 15 years ago, and there's a valve four our building five feet from the front of the building. We just have to bust open the sidewalk. Sidewall sprinkler isn't an option as we're in a row of 1855 buildings.
> 
> Acoustics shouldn't be a problem (I didn't see or hear of any specific requirement from the architect or city). Above the tin ceiling the floor assemble will be the original floor-boards, 23/32" plywood subfloor, 1/2" quickcrete over the electric radiant floor system, and then 3/4" hardwood.




Suggest you get 2-3 fire sprinkler companies to look at it, there are many ways to get pipe and sprinklers in strange places. 

You may need a four inch line tap off the street main, and coming into the building


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## redeyedfly (Mar 4, 2021)

Resident Artist said:


> I want to thank everyone for the input. We're getting quotes now for a sprinkler system. The city ran a dedicated fire-water line in the street 15 years ago, and there's a valve four our building five feet from the front of the building. We just have to bust open the sidewalk. Sidewall sprinkler isn't an option as we're in a row of 1855 buildings.
> 
> Acoustics shouldn't be a problem (I didn't see or hear of any specific requirement from the architect or city). Above the tin ceiling the floor assemble will be the original floor-boards, 23/32" plywood subfloor, 1/2" quickcrete over the electric radiant floor system, and then 3/4" hardwood.


I assume you mean "gypcrete" instead of "quickcrete".  Very likely you will need an acoustic mat below the gypcrete to get your sound rating.  You'll need to meet 50 STC & IIC.  It's the IIC that is difficult to achieve with hard surface flooring, acoustic mat works well to get to the required IIC.


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## Resident Artist (Mar 4, 2021)

Yes, gypcrete.


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## cda (Mar 4, 2021)

If you are going to install a fire sprinkler system

Look at chapter 4 live work, to see if it helps you save money!!!!!!!!!!


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## classicT (Mar 4, 2021)

cda said:


> If you are going to install a fire sprinkler system
> 
> Look at chapter 4 live work, to see if it helps you save money!!!!!!!!!!


CDA, you are really passionate about a Live/Work unit in this thread.

For the benefit of Resident Artist, here are the limitations that you must be able to comply with for a Live/Work Unit.

*419.1.1 Limitations*​All of the following shall apply to live/work areas:​
The live/work unit is permitted to be not greater than 3,000 square feet (279 m2) in area.
The nonresidential area is permitted to be not more than 50 percent of the area of each live/work unit.
The nonresidential area function shall be limited to the first or main floor only of the live/work unit.
Not more than five nonresidential workers or employees are allowed to occupy the nonresidential area at any one time.


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## Resident Artist (Mar 4, 2021)

Chapter 4? Can anyone give me a preview of how this helps with sprinklers?

We easily meet all of the 419.1.1 limitations.


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## classicT (Mar 4, 2021)

Resident Artist said:


> Chapter 4? Can anyone give me a preview of how this helps with sprinklers?
> 
> We easily meet all of the 419.1.1 limitations.


Go to this link for _IBC Section 419_








						Searchable platform for building codes
					

Explore a searchable database of US construction and building code. Code regulations are consolidated by state and city for easier navigation.




					up.codes


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## cda (Mar 4, 2021)

Resident Artist said:


> Chapter 4? Can anyone give me a preview of how this helps with sprinklers?
> 
> We easily meet all of the 419.1.1 limitations.




From post 25  up the road, courtesy of Fatboy





"Anyone want to say if live work helps???

cda,

Yes, it appears it could work. They would still have to install a sprinkler system, which they were trying to avoid. But, yes, they could dodge the separation requirement though.

_                  [F] 419.5 Fire protection. The live/work unit shall be provided with a monitored fire alarm system where required by Section 907.2.9 and an automatic                         sprinkler system in accordance with Section 903.2.8._

They meet the square foot requirements for the size overall, and the size of the business to residential ratio.

_                 419.1.1 Limitations. All of the following shall apply to live/work areas: 
                          1. The live/work unit is permitted to be not greater than 3,000 square feet (279 m2 ) in area. 
                          2. The nonresidential area is permitted to be not more than 50 percent of the area of each live/work unit. 
                          3. The nonresidential area function shall be limited to the first or main floor only of the live/work unit. 
                          4. Not more than five nonresidential workers or employees are allowed to occupy the nonresidential area at any one time._

Installing a fire sprinkler system in the walls would be an option to avoid penetrating the historic tin ceiling.

BTW, the analysis must have been using the 2015,   Chapter's 13 and 14 were reversed.


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## fatboy (Mar 4, 2021)

"I want to thank everyone for the input. We're getting quotes now for a sprinkler system. The city ran a dedicated fire-water line in the street 15 years ago, and there's a valve four our building five feet from the front of the building. We just have to bust open the sidewalk. Sidewall sprinkler isn't an option as we're in a row of 1855 buildings."

That is great, probably saved you about $15,000, at least around here, to get it from the main in the street, to that close to your building.


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## steveray (Mar 5, 2021)




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## fatboy (Mar 5, 2021)

hmmmm......


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## Paul Sweet (Mar 8, 2021)

A 45 mil thickness is likely to obscure most of the pattern in the tin.


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## fatboy (Mar 8, 2021)

Paul Sweet said:


> A 45 mil thickness is likely to obscure most of the pattern in the tin.


That is pretty thick.


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## classicT (Mar 8, 2021)

fatboy said:


> That is pretty thick.


Really?

It is slightly less than 3/64 of an inch.


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## fatboy (Mar 8, 2021)

Going towards Paul's comment of obscuring details on the tins, 45 mils, equilvalent of nine layers of  6 mil plastic sheeting?


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## RickAstoria (Sep 18, 2021)

Is it possible to carefully take down the tin ceiling, apply the flame-off stuff to what is likely a lath & plaster ceiling or you can apply a 1/2" gypsum board and then the spray on that flame-off and then put the tin ceiling back up. Just wondering if that would be possible? A thought. The tin ceiling are usually a "tile" not one singular piece the size of the room(s). Care would need to be taken when removing the tin and then reinstalling it back up afterwards. If you need add a gypsum board because there is no lath & plaster behind the tin ceiling then you can add the flame off stuff and then add your tin ceiling back up and wall mouldings at a slightly lower level (~1/2 to 5/8"). It might be doable without compromising the historic character.


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