Should bathroom ceiling drywall be moisture-resistant green board or regular drywall with paint?

For bathroom ceilings in the GTA, moisture-resistant drywall — commonly called green board — is the recommended choice, especially in bathrooms with showers or tubs where steam rises directly to the ceiling. While regular drywall with quality bathroom paint can work in low-moisture spaces like a powder room, the small extra cost of moisture-resistant board provides meaningful protection against the humidity that bathroom ceilings endure daily.

Green board (moisture-resistant gypsum board) uses a water-resistant paper facing and a wax-treated gypsum core that resists moisture absorption better than standard drywall. It costs roughly $2–$4 more per 4x8 sheet than regular drywall — a negligible premium when you consider the total cost of a bathroom renovation. For a standard GTA bathroom ceiling of 40–60 square feet, the material upgrade adds only $10–$25 to the project.

The Better Option: Purple Board or DensShield

If you're doing a full bathroom renovation and the ceiling is already open, consider going beyond green board. Purple board (mould-resistant drywall, such as Gold Bond Purple XP or CGC Mold Tough) offers significantly better mould resistance than standard green board. The paper facing is treated with a fibreglass mat that mould cannot feed on, making it the superior choice for bathroom ceilings that are exposed to steam from showers and baths. The cost premium is about $5–$8 per sheet over regular drywall.

For bathrooms with steam showers, the ceiling must be treated as a wet area. Regular green board or even purple board isn't sufficient for direct steam exposure. In a steam shower enclosure, the ceiling should use cement board (Durock, Wonderboard) or DensShield tile backer with a waterproof membrane, just like the walls. The ceiling inside a steam enclosure also needs to be sloped (at least 2 inches per foot) so condensation runs to the walls rather than dripping on the user.

Paint Matters Too

Regardless of which drywall you choose for the ceiling, the paint finish is critical. Use a 100% acrylic, mould-resistant bathroom paint in a semi-gloss or satin finish. Benjamin Moore Aura Bath & Spa and Dulux Kitchen & Bath are both widely available at GTA paint stores and are formulated for high-humidity environments. Semi-gloss finishes repel moisture better than flat or eggshell and are easier to clean. Apply at least two coats with proper drying time between coats.

Avoid flat or matte ceiling paint in bathrooms — while it hides imperfections, it absorbs moisture and is far more susceptible to mould growth and staining. The slight sheen of semi-gloss on a bathroom ceiling is a worthwhile trade-off for durability.

When Regular Drywall Is Acceptable

In a powder room or half bath — a bathroom with only a toilet and sink, no shower or tub — regular drywall with quality bathroom paint is perfectly adequate. There's minimal steam generation in a powder room, so moisture-resistant board isn't necessary. This is the one bathroom type where you can save the small premium without concern.

Painting your bathroom ceiling is a solid DIY project that can save $300–$600 in labour costs. Prep the surface properly, use painter's tape at the wall-ceiling junction, and apply mould-resistant bathroom paint with a roller for a smooth, even finish. If your bathroom renovation involves replacing the ceiling drywall itself, that's typically best left to a professional — drywall installation on ceilings is physically demanding and requires experience to get clean joints.