This just doesn’t seem correct. The garage was finished and then the house was upgraded from baseboard heat to forced air. The duct was cut through the garage ceiling drywall and the upstairs wood floor for the register in a couple of different rooms. Your thoughts please
It is a breach of the fire wall and a safety hazard. This hole can also allow carbon monoxide from a running vehicle into the living space.
The duct must be constructed of a material with a fire rating equal to the fire wall.
HVAC supply air boots and connectors must be insulated with 1 in. fiberglass, (R2) [IRC 1103.3]