Custom Residential Architects Network

As garage conversion to ADU is becoming more and more common, I am coming accross the issue of having to modify the existing floor/ceiling assembly to satisfy the requirement for frire separation, STC 50+ and ICC. This upgrade can be very inconvenient to home owners as they might have to remove the floor finish to provide a sound break underlayment, in addition to other imprvements that can be done from the floor below, specifically, for SFD over a garage.

I have been doing research and cannot seem to find a way to retrofit the assembly that can demonstrate an actual STC value. The plan checkers seem to rely on pre-approved system like from the Gypsum Association. 

Am I looking at this the wrong way? Is there a method to provide proof that by decoupling the ceiling, providing acoustical insulation, sealing gaps, adding mass, damping, etc., WITHOUT having to touch the existing floor finish above, it will provide an acceptable/equivalent level to STC?

have you checked HUD guidelines?

https://www.hud.gov/sites/documents/DOC_16419.PDF

As garage conversion to ADU is becoming more and more common, I am coming accross the issue of having to modify the existing floor/ceiling assembly to satisfy the requirement for frire separation, STC 50+ and ICC. This upgrade can be very inconvenient to home owners as they might have to remove the floor finish to provide a sound break underlayment, in addition to other imprvements that can be done from the floor below, specifically, for SFD over a garage.

I have been doing research and cannot seem to find a way to retrofit the assembly that can demonstrate an actual STC value. The plan checkers seem to rely on pre-approved system like from the Gypsum Association. 

Am I looking at this the wrong way? Is there a method to provide proof that by decoupling the ceiling, providing acoustical insulation, sealing gaps, adding mass, damping, etc., WITHOUT having to touch the existing floor finish above, it will provide an acceptable/equivalent level to STC?

As garage conversion to ADU is becoming more and more common, I am coming accross the issue of having to modify the existing floor/ceiling assembly to satisfy the requirement for frire separation, STC 50+ and ICC. This upgrade can be very inconvenient to home owners as they might have to remove the floor finish to provide a sound break underlayment, in addition to other imprvements that can be done from the floor below, specifically, for SFD over a garage.

I have been doing research and cannot seem to find a way to retrofit the assembly that can demonstrate an actual STC value. The plan checkers seem to rely on pre-approved system like from the Gypsum Association. 

Am I looking at this the wrong way? Is there a method to provide proof that by decoupling the ceiling, providing acoustical insulation, sealing gaps, adding mass, damping, etc., WITHOUT having to touch the existing floor finish above, it will provide an acceptable/equivalent level to STC?