Holes in the drywall between my Orleans garage and kitchen, a problem?

Yes, holes in the wall between your garage and your kitchen are worth dealing with. Ontario's Building Code (9.10.9.18.(4)) requires an air barrier system between an attached garage and the rest of the house that provides an effective barrier to gas and exhaust fumes, and holes break that barrier.

The Code's requirement is continuity. Joints in a panel-type air barrier must be sealed (9.25.3.3.(1)), and penetrations such as electrical wiring, electrical boxes, piping or ductwork must be sealed as well (9.25.3.3.(6)). A hole left open in that wall, whatever its size, is a gap in the barrier. These are minimums for new work; ask the City how they apply to your renovation.

What a contractor needs to do is patch the holes so the wall is continuous again, then seal every joint and penetration on the garage side. Many builders use taped and sealed drywall to form that gas barrier. The Code does not require a fire rating or 5/8-inch (15.9 mm) Type X drywall between a single home's attached garage and the house; what it requires is that the barrier is continuous and sealed. The door between the garage and the kitchen also needs to be tight-fitting, weather-stripped and fitted with a self-closing device (9.10.13.15.(1)); ask the contractor what they propose for the door and how it meets that clause.

Also worth checking: the Code says the doorway between a garage and the house must not open into a room intended for sleeping (9.10.13.15.(2)). A kitchen is fine on that point.

For the patch work itself, ask the quote to state:

• which board is being used and its thickness
• how the joints and penetrations on the garage side will be sealed
• whether the kitchen side will be finished and to what level
• what is included for the door, if the self-closing device needs attention

Get the scope of the sealing work described in writing, not just the patch count, so you can confirm the barrier is continuous once the job is done.