I am in the process of finishing a garage and have a question about how to deal with the gap between the drywall ceiling and the plastered wall, partly to make it look nice but above all to make it airtight as it is intended to be a living space above the garage and I don't want exhaust smells and other odors seeping through. Thank you in advance.
Soft sealant to seal? And if you don't like that look, you can always put crown molding on it.