What are typical prices for moisture-resistant drywall installation in a GTA bathroom or laundry room?

Moisture-resistant drywall installation in a GTA bathroom or laundry room typically costs $4.00 to $7.00 per square foot for board and installation, plus $2.00 to $3.50 per square foot for taping and finishing — putting a typical bathroom at $1,200 to $3,000 for the drywall scope alone. The premium over standard drywall reflects the higher material cost and the extra care required in high-moisture environments.

The first decision is which type of moisture-resistant board to use, and this is where many homeowners (and some contractors) make costly mistakes. Green board (moisture-resistant drywall with green paper facing) has been the standard for decades. It has a moisture-resistant core and water-repellent paper facing that resists humidity better than regular drywall. GTA pricing runs $20 to $28 per 4x8 sheet compared to $14 to $20 for standard board. Green board is appropriate for bathroom walls and ceilings that are exposed to humidity but not direct water contact — think the walls around the vanity, the ceiling above the shower, and laundry room walls.

Purple board (mould-resistant drywall like Georgia-Pacific's DensArmor or CGC's Mold Tough) is the superior choice and increasingly the standard recommendation for GTA bathrooms. Instead of paper facing, it uses fibreglass mat facing that eliminates the paper food source that mould needs to grow. At $24 to $32 per 4x8 sheet, it costs more than green board, but in Toronto's humid summers — when bathroom humidity can stay elevated for hours after showers — the extra mould resistance is worth every penny. For a typical bathroom with 250 to 400 square feet of wall and ceiling surface, the material upgrade from green to purple board adds only $100 to $200 to the total project cost.

One critical rule: neither green board nor purple board should be used as a tile substrate in shower or tub surrounds. Direct water exposure will eventually penetrate any gypsum-based product, no matter how moisture-resistant the facing. Shower and tub surrounds require cement board (Durock, HardieBacker, or equivalent) at $25 to $40 per 3x5 sheet, installed with proper waterproofing membrane behind it. The cement board handles the wet zone, and moisture-resistant drywall handles the rest of the room.

For a standard GTA bathroom (roughly 5x8 to 8x10 feet), here's what the drywall scope typically costs. The walls have about 200 to 350 square feet of surface once you subtract the vanity, shower/tub surround (which gets cement board), window, and door. The ceiling adds another 40 to 80 square feet. Using purple board throughout with a Level 4 finish, you're looking at $1,200 to $2,500 for materials, hanging, taping, and finishing.

A laundry room is generally simpler and less expensive because there's less moisture exposure than a bathroom (no shower steam), but moisture-resistant board is still the right choice. Washing machine leaks and dryer humidity make standard drywall a poor choice. A typical laundry room (6x8 to 8x10 feet) runs $800 to $1,800 for the drywall scope with moisture-resistant board.

Bathroom exhaust ventilation is critical and directly affects your drywall's longevity. Ontario Building Code requires mechanical ventilation in all bathrooms, and a properly sized exhaust fan (minimum 50 CFM for a standard bathroom, 1 CFM per square foot for larger bathrooms) is essential to remove moisture before it penetrates the drywall. Even mould-resistant board will develop problems if the bathroom has inadequate ventilation. Make sure your exhaust fan vents to the exterior — not into the attic, which is a shockingly common violation in older GTA homes.

GTA-specific humidity is a real concern here. Lake Ontario's moderating effect keeps lakefront neighbourhoods like the Beaches, Mimico, Port Credit, and Lakeshore slightly more humid year-round, making moisture-resistant board even more important in bathrooms in these areas. During summer months, when outdoor humidity combines with shower steam, bathrooms without adequate ventilation can sustain humidity levels above 70 percent — ideal conditions for mould growth behind standard drywall.

This is a project where professional installation pays for itself. Improper sealing around tub and shower edges, gaps at the floor line, and failure to maintain the vapour barrier integrity behind bathroom walls all lead to hidden moisture problems that won't show up for months or years — by which time the damage requires a complete tear-out. Get matched with experienced drywall contractors through Toronto Drywall Installers for free estimates.