What thickness and type of drywall should I buy for a garage ceiling in an Etobicoke home?

For a garage ceiling in an Etobicoke home, you need 5/8-inch Type X fire-rated drywall — this is not optional, it is required by the Ontario Building Code. The wall and ceiling assembly between an attached garage and the living space above must achieve a minimum 45-minute fire resistance rating, and standard 1/2-inch regular drywall does not meet this requirement. Type X drywall has a glass-fibre reinforced gypsum core that holds together under fire conditions long enough to allow occupants to escape.

The reason this matters so much in Etobicoke specifically is that the neighbourhood is dominated by post-war bungalows, side-splits, and raised ranches from the 1950s through 1980s — many of which have attached garages that were built before modern fire separation standards were as strictly enforced. If you are replacing an existing garage ceiling or finishing a garage that was previously left with exposed framing, this is your opportunity to bring the fire separation up to current code. Every joint must be taped and finished with compound, and any penetrations (light fixtures, wiring runs, plumbing pipes) must be properly sealed with fire-rated caulking or fire stop compound to maintain the integrity of the fire separation.

Why 5/8-inch and not 1/2-inch? Beyond the fire rating requirement, 5/8-inch drywall is inherently better for ceilings because it resists sagging. Garage ceilings often span the full width of the garage with framing at 16 or 24 inches on centre, and the heavier 5/8-inch board stays flat over these spans far better than 1/2-inch. If your garage ceiling joists are spaced at 24 inches on centre, 1/2-inch drywall will visibly sag between joists over time — even without the fire-rating requirement, 5/8-inch is the right choice for ceiling applications at that spacing.

At GTA suppliers, expect to pay $20–$28 per 4x8 sheet for 5/8-inch Type X drywall. For a standard two-car garage ceiling (roughly 400–500 square feet), you will need approximately 13–16 sheets of 4x8, though using 4x12 sheets reduces the number of joints and produces a cleaner result. Factor in an extra 10–15% for waste from cuts around garage door tracks, opener hardware, and light fixtures.

Additional Materials and Considerations

You will also need drywall screws rated for 5/8-inch board — use 1-5/8-inch coarse-thread screws, driven every 12 inches along each joist on the ceiling. A drywall screw gun with a depth-stop clutch is essential to avoid overdriving screws, which breaks the paper face and compromises holding power. For the joints, paper tape with setting compound (hot mud) is the best choice for the first coat in a garage environment, since garages are typically unheated in winter and the temperature fluctuations in Etobicoke's freeze-thaw climate can cause pre-mixed compound to cure poorly.

One important note: if your garage has a habitable room above it (a bedroom, home office, or bonus room), the fire separation requirement extends to the entire ceiling-floor assembly, and you may also need to address sound transmission. A single layer of 5/8-inch Type X on resilient channel provides both improved fire resistance and better sound isolation from the living space above.

This is a project where hiring a professional drywall contractor makes sense. Hanging 5/8-inch sheets overhead is physically demanding — each 4x8 sheet weighs approximately 70 pounds — and the fire-rating integrity depends on proper installation with no gaps, correctly spaced screws, and fully taped joints. A professional crew with a drywall lift can complete a two-car garage ceiling in a day. Expect to pay $3.50–$6.00 per square foot installed for fire-rated ceiling drywall in the GTA, including materials, labour, and finishing. For a typical Etobicoke garage, that works out to roughly $1,800–$3,000 for the complete drywall scope.