Repairing tape problems are more work than nail pops or drywall dents because you will be pulling off paper tape that is about 2" wide, thereby creating a larger repair area. But it is not hard to repair if you proceed as follows:
- Cut away the damaged section of drywall tape using a very sharp knife or break away razor utility tool. Then carefully pull off the damaged section of tape. You will also be pulling off little bits of dried drywall joint compound, that's OK.
- Using a 4" drywall flat blade taping knife (again, the cheap plastic type is OK), apply premixed drywall joint compound in the opened drywall joint as a bedding for the new tape. Make sure to apply the compound so it fully covers the tape width and length.
- Cut your new section of drywall tape to length.
- Using your slightly wetted 4" drywall flat blade taping knife, center the drywall tape on the joint and while holding the taping knife at about a 45 degree angle, run the knife down along the tape, pressing it fully and firmly into the joint compound bedding. Compound will ooze out around the edges and that is a good thing.
- Allow to dry overnight and scrape away any high spots with the taping knife the next day.
- Apply a second coat of joint compound using a 10" taping knife. Again using a slightly wetted taping knife, apply a second coat of premixed joint compound that is 6"-8" inches wide and covers thew first layer of compound.
- Holding the taping knife more at a 90 degree angle to the taped joint, draw it down the taped repair in one smooth stroke. Remove any excess from the edges. What yo want is the taped area to be fairly smooth. It may have some bubbles in it but that is OK.
- Allow to dry overnight and scrape away any high spots with the taping knife the next day.
- Apply the third and final coat of joint compound again using a slightly wetted 10" taping knife. Apply the joint compound to an area that is about 8" to 10" wide.
- Allow to dry overnight and scrape away any high spots with the taping knife the next day, then lightly sand using a sanding block and about 200 grit sand paper.
- Once dry, check the repair. If the compound shrunk or you see pitting, repeat the application of joint compound and sanding.
- Once the repair is dry and sanded smooth (close your eyes and feel the repair with your hand) the you can prime and paint.
