The final step in hanging drywall is the most important and the most difficult one – joint finishing. It is the most important because on it depends the final look of the wall and it is difficult because it requires knowledge, patience and effort.

In principle this is a straight forward operation:

  • All the joints and fasteners dimples will be filled with drywall compound
  • Usually three coats of compound will be applied
  • Joint tape is embedded in the compound when the first coat is applied (joints and inside corners)
  • Metal corners on outside corners are covered with compound
  • Sanding the compound covered joints gives the finished quality to the wall

Tips to keep in mind:

  • Maintain a temperature of at least 55 F
  • Avoid getting dry compound in the fresh compound
  • To make oyur life easier during sanding keep the coats thin and smooth
  • Move slowly, don’t hurry, more so when you embed the tape in the compound

First coat

  • Flat joints
    • Use a 5″ finishing knife
    • For each joint apply a thin and even coat of drywall compound for the full lenght of the joint
    • Apply the tape and press it with your fingers so it adheres to the compound
    • Use the finishing knife to embed the tape in the compound by drwaing it at a 45 degree angle, in both directions, starting at the middle of the joint
    • Make sure there is still compound under the tape but not more than 1/32″ (less than 1 mm)
    • Apply a thin coat of compound over the tape to fully cover it
  • Fasteners (nail or screw heads)
    • Use a 5″ finishing knife
    • Fill each dimple with compound
    • Make sure no nail or screw head is visible (if it is then drive it in correctly)
    • Don’t leave excess material around the dimple (you will have to sand it)
  • Inside corners
    • Use a 5″ finishing knife
    • Apply a thin layer of drywall compound on both sides of the corner
    • Fold the tape and press it woth your fingers so it adheres to the compound
    • Use the finishing knife to embed the tape in the compound by drwaing it at a 45 degree angle, in both directions, starting at the middle of the joint. Make sure not to cut the tape with the knife!
    • Make sure there is still compound under the tape but not more than 1/32″ (less than 1 mm)
    • Apply a thin coat of compound over the tape to fully cover it
  • Outside corners and metal trims
    • Use a 5″ finishing knife
    • Work one side at a time
    • Apply compound 5″ wide
    • Draw the knife with one edge on the nose of the metal bead and the other edge on the wall
    • Apply a second and a thirs coat making them 2″ wider each time (use a wider finishing knife for better results)

Second coat

  • Flat joints
    • Wait until the first coat has dried (at least 24 h)
    • Use a 8″ finishing knife
    • Clean the surface of the first coat to remove bumps (use the finishing knife or sanding paper)
    • Apply compound wider than the first coat (8″) for tappered joints
    • Apply compound for 7″ wide on each side of a butt joint for a width of 14″ in total
  • Fasteners (nail or screw heads)
    • Repeat the procedure used for the first coat
  • Inside corners
    • Wait until the first coat has dried (at least 24 h)
    • Use a 5″ finishing knife
    • Clean the surface of the first coat to remove bumps (use the finishing knife or sanding paper)
    • Apply compound one side at a time
    • Extend the compound 2″ wider than the first coat
    • Wait for one side to dry before working on the second side
  • Outside corners and metal trims
    • Wait until the first coat has dried (at least 24 h)
    • Use a 8″ finishing knife
    • Clean the surface of the first coat to remove bumps (use the finishing knife or sanding paper)
    • Extend the compound slightly wider than the first coat

Third coat (thin finishing coat)

  • Flat joints
    • Wait until the second coat has dried (at least 24 h)
    • Use a 10″ finishing knife
    • Clean the surface of the second coat to remove bumps (use the finishing knife or sanding paper)
    • Apply the finishing coat by pressing the knife firmly. You want the depressions filled while the coat stays really thin.
  • Fasteners (nail or screw heads)
    • Repeat the procedure used for the first and second coat
  • Inside corners
    • Wait until the first coat has dried (at least 24 h)
    • Use a 8″ finishing knife
    • Clean the surface of the first coat to remove bumps (use sanding paper)
    • Apply compound one side at a time
    • Extend the compound 2″ wider than the second coat
    • Wait for one side to dry before working on the second side
  • Outside corners and metal trims
    • Wait until the second coat has dried (at least 24 h)
    • Use a 10″ finishing knife
    • Clean the surface of the second coat to remove bumps (use sanding paper)
    • Extend the compound slightly wider than the second coat

Sanding

  • Use a fine grade (80/100 grit) open coat sandpaper after the first two coats (if needed)
  • Use a 120 grit sandpaper for the final sanding
  • Wrap the sandpaper around a wood block or use a pole sander
  • Sand lightly to remove imprefections
  • Don’t sand on the drywall to avoid roughening the paper surface of the drywall
  • Remove the dust using a damp sponge
  • Use all the time a dust mask
  • Make sure the room is well ventilated

Now the last step before painting the wall is to apply primer.

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