What is the price difference between standard and fire-rated drywall for a Toronto garage conversion?

The material cost difference between standard 1/2-inch drywall and fire-rated 5/8-inch Type X drywall is only about $4 to $10 per 4x8 sheet — but in a Toronto garage conversion, fire-rated Type X drywall isn't optional. Ontario Building Code requires it on the garage side of any wall or ceiling separating the garage from the living space, and using standard drywall in this application is a code violation that creates a serious life-safety hazard. The total cost difference for a typical single-car garage conversion runs $500 to $1,500 more for fire-rated assemblies compared to standard drywall throughout.

Let's break down exactly what Ontario Building Code requires and what it costs. The garage-to-house fire separation must achieve a minimum 45-minute fire resistance rating. This means the wall and ceiling between the attached garage and the living space must use 5/8-inch Type X drywall on the garage side, with all joints properly taped and finished — no gaps, no unsealed penetrations, no missing sections. The door between the garage and the living space must be a solid-core or fire-rated door with a self-closing mechanism. These aren't suggestions — they're code requirements that your building inspector will verify, and any garage conversion in Toronto requires a building permit.

Standard 1/2-inch drywall costs $14 to $20 per 4x8 sheet at GTA building supply stores. Fire-rated 5/8-inch Type X drywall costs $20 to $28 per sheet. The Type X designation means the gypsum core is reinforced with glass fibres that hold the board together longer during a fire, providing the rated fire resistance. It's also thicker and heavier — a 4x8 sheet of 5/8-inch Type X weighs about 70 pounds compared to 50 pounds for standard 1/2-inch, which means more labour to handle and install.

For a typical single-car garage (roughly 12x20 feet), the fire separation includes the shared wall with the house (about 160 square feet) and the ceiling if there's living space above (240 square feet). That's 400 square feet of fire-rated surface requiring approximately 13 to 15 sheets of Type X board. At $6 to $8 more per sheet than standard, the material premium for the fire-rated sections is only $80 to $120. The real cost difference comes from the labour — Type X is heavier to hang, the thicker board requires more compound to achieve flush joints, and the installer must ensure every joint, corner, and penetration is properly sealed to maintain the fire rating.

The total drywall cost for a garage conversion including all walls, ceiling, taping, and finishing typically runs $4,000 to $10,000. The breakdown looks like this: fire-rated Type X on the shared wall and ceiling at $3.50 to $6.00 per square foot installed and finished; standard drywall on the new exterior walls (over insulation and vapour barrier) at $2.50 to $4.00 per square foot; plus any interior partition walls at $2.50 to $4.00 per square foot. The fire-rated sections add roughly $500 to $1,500 to the total project cost compared to using standard board everywhere — a small premium for a critical safety feature.

Beyond the fire-rated drywall, a garage conversion involves several other code requirements that affect your budget. Insulation is required on all exterior walls — minimum R-24 for above-grade walls, with a 6-mil polyethylene vapour barrier on the warm side. The concrete floor needs insulation and a subfloor system if it's being converted to living space. Electrical and HVAC modifications require their own permits and inspections. The total cost for a complete garage conversion in the GTA typically ranges from $15,000 to $40,000 depending on the scope, with drywall representing roughly 25 to 30 percent of the total.

One scenario that pushes fire-rated costs higher is when the garage has living space above it — a common layout in GTA homes where the second floor extends over the garage. In this case, the entire garage ceiling needs Type X drywall, and if the floor assembly between the garage and the room above doesn't already meet the fire resistance requirement, additional layers of Type X may be needed. A Type C board ($28 to $38 per sheet) provides enhanced fire resistance for situations where a 2-hour rating is required.

This is not a DIY project. Fire-rated assemblies must be installed correctly to provide their rated protection — a gap in the taping, an unsealed electrical box penetration, or a missing section of Type X drywall compromises the entire fire separation. Your building inspector will check these details, and getting it wrong means tearing it apart and redoing it. Get quotes from experienced contractors who understand fire separation requirements. Toronto Drywall Installers can match you with qualified drywall professionals through the Toronto Construction Network for free estimates on your garage conversion.