How to Install Moisture-Resistant Drywall in a Bathroom

Bathrooms are drywall killers. Steam rises, condensation pools on cold surfaces, and moisture seeps into standard gypsum board until it swells, softens, and invites mold. Moisture-resistant drywall—commonly called greenboard, blueboard, or cement board—is engineered to resist water damage where ordinary drywall would fail within months. The installation process is nearly identical to standard drywall, but the material is denser, heavier, and demands attention to sealing and ventilation. Done right, it keeps your bathroom walls solid for decades. Done wrong, you're just postponing the inevitable rot. The key difference isn't magic coating—it's core density and the resin binders that resist moisture penetration. You'll still tape and mud the seams, prime everything, and rely on exhaust fans to move moisture out of the room. The material itself buys you insurance, not immunity. If you've hung drywall before, you'll recognize every step. If this is your first time, the process is straightforward enough for a weekend project with a helper.

1. Map walls before you lift. Measure the wall height and width, then snap chalk lines on the studs where drywall edges will fall. Studs should be 16 inches on center. Check for plumbing lines, electrical outlets, and vent pipes, and mark their locations clearly on the studs. Moisture-resistant drywall is heavier than standard drywall—recruit a helper before you start hanging.
2. Cut clean holes first. Lay the first sheet flat on sawhorses. Use a straightedge and utility knife to score and snap drywall for straight cuts. For outlet holes and irregular shapes, use a drywall saw or hole saw. Cut from the face side so the finished face stays clean. Moisture-resistant board is harder to cut than standard drywall, so take your time and use a sharp blade.
3. Screw tight, not crushed. Lift the first sheet with your helper and position it tight to the top plate, flush to the corner. Drive drywall screws every 12 inches along studs and every 16 inches across the middle of the sheet, seating them just below the surface without crushing the paper. Start at the top and work downward. The heavier weight of moisture-resistant board means two people are essential here.
4. Offset seams for strength. Hang the second sheet horizontally offset from the first so seams don't align vertically—this adds structural strength. Continue across and down until all walls are covered. Leave a 1/8-inch gap at the ceiling and floor for settling and air movement; you'll cover this with trim later. Around tub and shower areas, extend coverage at least 5 feet up the wall.
5. Three coats, feathered wide. Apply a thin bed of joint compound along each seam using a 6-inch mud knife. Embed drywall tape into the compound, then cover with a second thin layer. Let it dry, then sand smooth. Apply a second coat over the tape with a 10-inch knife, feathering the edges. A third coat with a 12-inch knife creates a seamless finish. Use only moisture-resistant joint compound in bathrooms; regular drywall mud absorbs water.
6. Seal before you paint. Sand all mudded seams smooth with 120-grit sandpaper. Vacuum dust completely. Apply a moisture-blocking primer to all drywall surfaces, paying special attention to seams, fastener holes, and any cuts. The primer seals the paper and compound, preventing moisture penetration before paint. Two coats are ideal in high-moisture areas like directly above a tub or behind a shower surround.
7. Caulk where water wins. Apply two coats of bathroom-grade or semigloss paint (semigloss is more moisture-resistant and wipeable than matte). Pay special attention to corners, seams, and edges. After paint dries, run a bead of 100% silicone caulk along the top edge where drywall meets the ceiling and along any seams within 12 inches of the tub or shower enclosure. Caulk is more flexible than mud and won't crack under repeated moisture cycling.
8. Exhaust wins the war. Ensure the bathroom exhaust fan is installed and ducted to the exterior (not into an attic or soffit, which traps moisture). Run the fan during and for 20 minutes after every shower. A timer-controlled fan running automatically is more reliable than manual operation. Adequate ventilation removes moisture before it has time to penetrate even moisture-resistant drywall.