I'm building a basement rental unit in our home. We'll be living upstairs so I'm doing my best to sound separate the upper and lower units. I'm using a seperate hvac system for the basement (baseboard heating) so we won't be sharing supply and return lines. Also, I'm using Rockwool Safe'n'Sound in the basement ceiling in combination with resilient channel to deaden the noise coming from above.

My current issue is that the HVAC design for upstair, as it currently stands, uses panned floor joists for a number of return branch lines. This will leave a number of large sound proofing breaches in the ceiling, since the return cavities will be missing the rockwool insulation.

Is there a way I can fix this breach while maintaining panned return? My initial thought was to install some sort of insulation in the interior return, but I'm not sure what's safe/to code in that case.

I've also wondered if I could install the panning higher up in the cavity and then just add rockswool in the space underneath.

I'm in South Western, Ontario, and the build will need to pass inspection.

Thanks for your input!

1 Answer 1


Raising the floor of the duct will restrict airflow it's best to not do too much of that.

You could possibly apply soundproofing to the back of the drywall where the duct is. or just squash it between the duct and the drywall.

replacing the metal skin with wood or drywall will help too.

spray-on automotive soundproofing is another possibility.

A pan duct typically starts with a hole in the floor, that will let lots of sound through, lining the start of the duct with carpet or other sound absorbing material will help there.

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