Sound/Fire Proofing Finished Basement Ceiling for Accessory Dwelling Unit

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Posted by: from Bradford
4/30/2021 at 6:28:57 AM


We have a finished basement apartment that came with the house when we bought it. I want to get the apartment registered with the Town of BWG as an accessory unit to rent it out in future if need be. I applied for a permit and was advised that I need to rip out the current ceiling, sound proof it with insulation and resiliant channels and then replace the drywall be fire rated one. That work alone is being quoted for approximately $6500 to $9000 labour and material included. I feel that there has to be another way to bring my basement up to code without removing the current ceiling. Any suggestion/advice is greatly appreciated.

Thanks in Advance.

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Date/Time4/30/2021 at 10:14:31 AM

If the city allows you , you can double stack fire rated drywall on top of your ceiling without removing your ceiling

Because the only part that is important for you to rent the downstairs from your upper floor, this a stop the fire Form reaching either of you guys and to give you time to leave the house.

and you don't need to sound proof with insulation this is only an option by the homeowner if you wanted to soundproof it So the tenant downstairs don't have to hear you walk over their heads Or hear each other's conversation

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Ian in Edmonton
Date/Time4/30/2021 at 10:33:38 AM

In Alberta it's not required to have fire-rated drywall for a secondary suite. Article reads "Floor assemblies contained within dwelling units and within houses with a secondary suite need not be constructed as fire separations." Therefore only regular 1/2" drywall is required.

Regarding sound transmission the current (2019) Code has introduced requirements for secondary suites - requiring an STC (Sound Transmission Class) rating of 43. There are tables in the Code which illustrate a wide variety of assemblies and their associated STC (and fire resistance) ratings. The advice that you received from the town may be correct on this matter.

There may be a number of other development and Building Code requirements your town didn't inform you of which could cause further hiccups with your plan to legalize the suite; it would be best if you could find someone knowledgeable to inspect your home before you proceed too far and find there is more to be done. For example, you cannot mix conditioned air between the suites (separate furnaces) and the furnace room is required to be fully protected with drywall.

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Ian in Edmonton
Date/Time5/3/2021 at 4:26:53 PM

Just a little more info to better answer your question. The Table provided in the Code shows that adding a layer of 1/2" Type X gypsum board to the existing assembly would only provide an STC rating of 33 (Table, far below what's required (STC 43).

The Code also specifically talks about the 150 mm of sound absorbing insulation + resilient channels as your municipality has suggested. (Article, with an alternative of an assembly meeting the STC of 43.

Hope this better answers your questions.


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