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Retrofit ceiling/ floor for ADU

J

J2architect

Sawhorse
Joined
Apr 29, 2015
Messages
4
Location
Whittier, ca
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?
 
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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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....
 
J2architect said:
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?
Click to expand...

Welcome !!!!

Took you long enough to formulate a question
 
Build
J2architect said:
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?
Click to expand...


Build a one hour ceiling on 1st floor

If you can reference IBC, try a calculated approach
 
ICE said:
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
Click to expand...

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?
 
J2architect said:
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?
Click to expand...

Besides the sound you only need one hour rating??

Densglass shaftliner or similar or once again IBC and calculate it
 
Read thru this and see if any help


Existing Home Garage Conversion to ADU

If the joist are 16" OC then you can use IBC chapter 7 other wise it is not hard to find one hour floor ceiling assemblies Remember the fireside is the ceiling and 2 layers of type X or C is all most assemblies use The fireside for supporting construction in the conversion of the garage is the...
www.thebuildingcodeforum.com
 
cda said:
Read thru this and see if any help


Existing Home Garage Conversion to ADU

If the joist are 16" OC then you can use IBC chapter 7 other wise it is not hard to find one hour floor ceiling assemblies Remember the fireside is the ceiling and 2 layers of type X or C is all most assemblies use The fireside for supporting construction in the conversion of the garage is the...
www.thebuildingcodeforum.com
Click to expand...

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.
 
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???????????
 
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:
 
J2architect said:
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.
Click to expand...
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.
 
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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