Sanding the Walls

• Drywall compound must have a slightly rough surface that lets the compound fully adhere to the walls. You usually add drywall tape to the drywall and paint the compound on top of the tape. For touch-ups and other fixes in the bathrooms, lightly sand down the walls with the medium-grit sandpaper. Sanding the area gives the walls the same texture and grit as drywall and lets the tape better adhere to the surface. Use either a fiber mesh-style drywall tape or paper drywall tape.
  
  

Mudding the Wall

• Apply the drywall mud to the wall with a trowel, smoothing the mud into an even layer. Once the mud dries, check the surface carefully and look for any signs of tape sticking out or bumps on the surface. Use a utility knife and cut or trim those areas away from the wall. Apply more drywall compound and cover the cut-out areas. Sand down the entire wall with medium-grit sandpaper, picking one of 120-grit or less. Apply a second layer of drywall compound and after it dries, sand again.
  
  

Considerations

• It is not mandatory that you sand a painted bathroom wall before mudding, but it is beneficial. For minor damage, including small cracks or dents, simply apply the drywall compound directly to the wall. Once the compound dries, lightly sand down the surface and apply a second coat. Use a thin layer of compound each time and sand between layers, until the compound covers the damage. Sand the surface, making it sit even with the surrounding wall, and paint in a matching shade. For larger damaged areas, the compound needs the rough texture that sanding creates for proper adhesion.
  
  

Warning

• When repairing minor damage to your bathroom walls, you only need drywall compound. If you removed mold or other damage that left the Sheetrock or original drywall exposed, then you must use some form of drywall tape. The drywall tape keeps the compound firmly attached to the drywall and stops the compound from peeling away or chipping off the wall.