Assess damage before patching
Stop the water source first. Surface stains on paint-only moisture may dry and repaint — if gypsum core is firm and not delaminated, seal stain with primer and touch up paint.
Replace board that is swollen, soft, crumbling, or moldy behind the face paper. Probe with a screwdriver — mushy core means cut back to solid gypsum and dry framing.
- Dry cavity with fans/dehumidifier before close-in
- Cut square beyond all soft material
- Treat framing with mold cleaner if growth present
- Verify leak repair — new drywall fails if moisture returns
Cut-out and patch steps
Mark a rectangle spanning studs; cut along center of studs so patch screws land on solid framing. Add backing if hole falls mid-bay. Hang matching thickness — 1/2 inch most common; garages may be 5/8.
Tape with paper on flat repairs; mesh only on small patches. Feather mud wider than usual (12–16 inches) to hide humps under existing orange peel or knockdown.
Material for repairs
Small ceiling patches may need one sheet shared across several jobs — buy one 4×8 and cut studs accordingly. Match MR board in baths if the wet zone was MR.
For multi-room flood work, tally all cut-out areas and run our drywall calculator with a custom small-room entry — add 15% waste on irregular cutouts. See patching holes guide for backer and tape detail on small openings.