How to Repair a Seam on a Ceiling

How to repair a seam on a ceiling

• 1

  Measure the seam that has appeared in your ceiling. Unroll a paper tape along the seam and use the edge of a joint knife to cut it, but make it a little longer than the seam.

• 2

  Apply the joint compound with the joint knife, covering the seam at a width of about one-half inch.

• 3

  Apply the tape over the newly-applied joint compound and lightly press it onto the mud. Cut the tape squarely at the ends of the seam.

• 4

  Skim over the tape by pressing the joint knife along the tape, squeezing out any excess compound. Try to remove as much mud as possible. Move the knife in the opposite direction to finish off the other end of the seam.

• 5

  Let the first coat dry, then apply a second coat of mud using a wider joint knife. Use horizontal strokes to fill in any gaps and to make for a smoother finish.

• 6

  Smooth out the seam with the broad joint knife, skimming excess mud by "floating" the knife over the seam. This means not pressing the knife too hard as it may cause a bowing effect on the seam.

• 7

  Level the seam. Hold an edge of the knife against the seam at a 90 degree angle to the ceiling. If any gaps are noticeable between the blade and the wall, fill it in with extra layers of mud. Let the mud dry before finishing it off with light sanding.