How much does it cost to install mould-resistant drywall in all bathrooms during a Vaughan home renovation?

Installing mould-resistant drywall in all bathrooms during a Vaughan home renovation typically costs $3.50–$6.00 per square foot for materials and labour combined, depending on the board type chosen and the complexity of the bathroom layout. For a typical Vaughan home with two full bathrooms and a powder room, expect to spend $2,500–$5,500 for the drywall scope alone — that includes removal of existing drywall, new mould-resistant board, taping, finishing, and priming.

The two main mould-resistant options you'll encounter in the GTA market are green board (moisture-resistant drywall) at $20–$28 per 4x8 sheet, and purple board (mould-resistant drywall) at $24–$32 per 4x8 sheet. Green board has a moisture-resistant core and treated paper facing, which helps in moderately damp areas like powder rooms and kitchen walls. Purple board, however, uses a fibreglass facing instead of paper — since mould feeds on paper, eliminating it entirely makes purple board the superior choice for full bathrooms with showers and tubs. A third option, DensArmor Plus, uses fibreglass mat facing and runs $30–$40 per sheet, offering commercial-grade mould protection for homeowners who want the best available.

It's worth noting that no drywall product — not even purple board — is appropriate for direct use inside shower or tub surrounds. Those areas require cement board (Durock, HardieBacker) at $25–$40 per 3x5 sheet as the tile substrate. Mould-resistant drywall is designed for the walls and ceilings surrounding the wet zone, not inside it. A common mistake in GTA bathroom renovations is using green board behind tile in a shower stall — the board will eventually absorb moisture through grout joints and fail, requiring a costly tear-out and redo.

Vaughan's housing stock plays a role in pricing. Many Vaughan homes built in the 1990s–2000s have standard 1/2-inch regular drywall in bathrooms, often with inadequate ventilation fans. During a renovation, your contractor should also verify that the bathroom exhaust fan is properly ducted to the exterior (not into the attic, which is surprisingly common in older Vaughan subdivisions) and that it meets the minimum 50 CFM capacity for bathrooms. Without proper ventilation, even mould-resistant drywall will eventually develop surface mould from persistent condensation.

The vapour barrier situation matters too. On exterior bathroom walls in Ontario's Climate Zone 6, a 6-mil polyethylene vapour barrier must be installed on the warm side (between insulation and drywall) per the Ontario Building Code. If your contractor is opening up the walls during the renovation, this is the time to verify the vapour barrier is intact and properly sealed — especially in bathrooms where hot showers generate significant moisture.

For a breakdown of a typical Vaughan three-bathroom renovation, here's what to expect. A powder room (roughly 25–35 square feet of wall area) can be done with green board for $200–$400 total since moisture exposure is minimal. Full bathrooms (100–150 square feet of wall and ceiling area each) should get purple board or DensArmor Plus for $500–$1,200 per bathroom including labour. If you're doing a complete gut renovation with new framing, insulation, vapour barrier, electrical, and plumbing behind the walls, the drywall scope is just one piece of a project that typically runs $15,000–$35,000 per bathroom in the Vaughan market.

Timing your renovation matters in the GTA. Summer bathroom renovations in Vaughan deal with high humidity (humidex regularly exceeding 40), which slows compound drying and increases the risk of mould establishing itself before the walls are even painted. Your drywall contractor should use setting compound (hot mud) rather than pre-mixed compound in summer bathroom work, as it cures by chemical reaction regardless of humidity. Winter work in heated homes is actually ideal for drywall finishing — the dry indoor air helps compound cure cleanly.

This is absolutely a project for a professional drywall contractor. Bathroom drywall involves cutting around plumbing penetrations, shower valves, exhaust fans, and light fixtures while maintaining the integrity of the moisture and vapour barriers. A botched installation traps moisture in the wall cavity, and you won't know about it until mould is well established — at which point the entire wall needs to come down again. Get matched with a drywall contractor through the Toronto Construction Network for a free estimate on your project.