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Retrofit ceiling/ floor for ADU

J2architect

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Apr 29, 2015
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We have a 2 story type V building with 2 apartment units on the 2nd floor and we are converting an existing storage space on the 1st floor into an ADU. how do you retrofit the floor between units to comply with the 1 hour fire rating and 50 stc requirement without having to tear out the finish floor on the upper units? Is there a UL or certified testing number we can use to respond to the plan check comment?
 

ICE

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Well then I learned something new today. I didn't know that an apartment building is fair game for an ADU. Are you within the city of Whittier or the unincorporated part of Whittier?

GA FILE NO. FC 5120
 
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mark handler

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So. CA
FIND A TESTED ASSEMBLY THAT IS CONSISTENT WITH THE FRAMING AND HAVE THE ALTER THE CONSTRUCTION TO MATCH

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AN ARCHITECT SHOULD KNOW THIS STUFF....
 

mark handler

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Well then I learned something new today. I didn't know that an apartment building is fair game for an ADU. Are you within the city of Whittier or the unincorporated part of Whittier?
AS OF JANUARY 2020
 

cda

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We have a 2 story type V building with 2 apartment units on the 2nd floor and we are converting an existing storage space on the 1st floor into an ADU. how do you retrofit the floor between units to comply with the 1 hour fire rating and 50 stc requirement without having to tear out the finish floor on the upper units? Is there a UL or certified testing number we can use to respond to the plan check comment?

Welcome !!!!

Took you long enough to formulate a question
 

cda

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Build
We have a 2 story type V building with 2 apartment units on the 2nd floor and we are converting an existing storage space on the 1st floor into an ADU. how do you retrofit the floor between units to comply with the 1 hour fire rating and 50 stc requirement without having to tear out the finish floor on the upper units? Is there a UL or certified testing number we can use to respond to the plan check comment?


Build a one hour ceiling on 1st floor

If you can reference IBC, try a calculated approach
 

J2architect

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Whittier, ca
Well then I learned something new today. I didn't know that an apartment building is fair game for an ADU. Are you within the city of Whittier or the unincorporated part of Whittier?

GA FILE NO. FC 5120

I am within the city but this applies throughout California. Thank you for the GA file, but this applies to new construction, do you know if there is another method for existing floor/ ceiling to be retrofitted from the underside?
 

cda

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I am within the city but this applies throughout California. Thank you for the GA file, but this applies to new construction, do you know if there is another method for existing floor/ ceiling to be retrofitted from the underside?

Besides the sound you only need one hour rating??

Densglass shaftliner or similar or once again IBC and calculate it
 

cda

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Sorry I know nothing about stc 50, but if you make your own sandwich of some type using this

TABLE 721.2.1.4(2)
TIME ASSIGNED TO FINISH MATERIALS ON FIRE-EXPOSED SIDE OF WALL

And sound material to get stc 50???????????
 

Paul Sweet

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Richmond, VA
Gypsum Association GA-610-02 discusses membrane protection for existing unrated assemblies. It might no longer be available.

Gypsum Association GA-600-2018 Fire Resistance and Sound Control Design Manual has the most current listing of rated assemblies. The 2012 edition can be viewed on-line:
 

Robert

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Jan 29, 2016
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242
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Pinole, CA
Thank you for the suggestion. I am running into the same issue as he did. Trying to find an existing assembly that meets the stc 50 requirement.
You can always field test the assembly after construction rather than rely on an existing tested assembly for sound. The advantage is they give you an extra 5db allowable, The disadvantage is, if it doesn't pass you are left with fixing it to comply.
 

MACV

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Jul 12, 2020
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Location
Massachusetts
Try Kinetics IsoMax or equal "resilient sound isolation clips" and hat channels (RSIC-1). UL Design No. L583 (two layers 5/8" type X drywall for 1 hr.)
 
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