Quck answer
To fix a bubble in drywall tape, follow these steps:
1. Cut a small slit in the center of the bubble using a utility knife.
2. Use a putty knife to gently lift the edges of the bubble and apply joint compound underneath.
3. Smooth out the joint compound with the putty knife, ensuring it is level with the surrounding area.
4. Press down on the tape to remove any excess joint compound and air pockets.
5. Apply another layer of joint compound over the repaired area, feathering the edges to blend it with the rest of the wall.
6. Allow the joint compound to dry completely.
7. Sand the area lightly to create a smooth finish.
8. Finally, prime and paint the repaired section of the wall to match the rest.
When using paper tape to cover drywall seams, it is common to encounter at least one bubble. This occurs because an insufficient amount of drywall joint compound (mud) was applied to the seam before applying the tape. As a result, the tape separates from the joint and forms a bubble. This issue can be avoided by using fiberglass mesh tape.
It is important to address bubbles before applying texture and paint, as they will be visible on the finished surface. If left unattended, the mud may crack months later, requiring the joint to be repaired and repainted. While not a major problem, it can be quite inconvenient.
Technique #1: Replace the Tape
If a bubble appears while taping and applying the first coat of mud, you can follow these steps to remove it:
- Create an outline in the fresh mud using the corner of your mudding trowel.
- Use a sharp utility knife to cut along the outline. Then, grab a corner of the cut-out tape and lift it away.
- If the bubble does not extend over the joint, simply cover the gap with mud. This may create a slight indentation, but it should disappear when the second coat is applied. If not, it will definitely disappear with the third coat.
- If the bubble extends across the joint, cut the tape along its entire width on both sides of the bubble and remove it. Apply fresh mud to the joint and place a new piece of tape that overlaps the cut edges by about 1/2 inch. Spread a coat of mud over the new tape, allow it to dry, and then apply the second and third coats.
Technique #2: Apply Mud Under the Tape
Another way to fix a bubble while taping is to spread additional mud underneath the lifted section.
If the bubble is near the edge of the tape, lift that edge and apply joint compound underneath it. Scrape the tape onto the fresh mud to secure it, and then apply another coat over it.
If the bubble spans the seam, make two vertical cuts on each side of the bubble that are slightly longer than its width, but do not reach the tape edges. Make a third cut along the seam that extends to the two vertical lines, and then fold back the two halves of the tape. Apply fresh mud to the seam, place the two halves back in position, scrape them flat, and apply a coat of mud over them.
Repairing Bubbles After Mud Has Dried
At times, bubbles may go unnoticed until the mud has dried and begins to crack, which could be long after the wall has been painted. In such cases, the only solution is to cut out the bubble and apply new tape.
- Remove the cracked mud by using a drywall trowel.
- Eliminate the bubbled section of tape and clean the joint with a damp cloth to remove any remaining dried mud particles.
- Apply a new layer of mud over the removed section and place new tape on top, ensuring it overlaps with the existing tape by at least half an inch.
- Smooth over the new tape to embed it in the mud, then apply two or more coats of fresh mud, allowing each coat to dry before applying the next.
- Use 120-grit sandpaper to level the repaired area and then apply a coat of drywall primer. Touch up the texture and paint after the primer has dried.
