How to repair plasterboard with joint tape

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In the same way that joint tape is used to bridge the gap between sheets of plasterboard, it can also be used to conceal the seams between an existing sheet and the smaller piece used to restore it.

The studs will be used as a base upon which the replacement piece of plasterboard will be fixed.

Step 1 – Mark and cut damaged area

With a pencil and ruler, draw a rectangle around the damaged area of plasterboard. If possible, the rectangle you have marked should reach the wall studs on either one or both sides.

Then, using a trimming knife, carefully cut out the rectangle you have marked.

Step 2 – Install back board

If your cut rectangle does not reach the wall studs on each side, you will need to install a back board on the underside of the plasterboard to support the new piece.

This can be done using either jointing compound or drywall screws. If using compound, wait for it to dry completely before moving onto the next step.

Step 3 – Position new piece of plasterboard

Cut a patch of plasterboard only very slightly smaller than the hole you have cut.

Apply jointing compound to both the stud and back block on either side of the hole, then carefully place the patch of plasterboard into the hole. Wait for the compound to dry.

Step 4 – Apply base layer of jointing compound (if using paper tape)

If you are using paper jointing tape, with a 150mm taping knife, apply jointing compound around the joints between the patch and the main sheet of plasterboard.

Step 5 – Apply tape

Apply four lengths of tape to the joints around the patch (one for each of the four sides of the patch).

If you are using paper tape, it will be put on top of the base layer of compound. If you are using scrim tape, it can be stuck directly onto the joint. Run your taping knife along the tape to get rid of any air bubbles and secure it into position.

Step 6 – Cover tape with compound

Load your taping knife with compound and apply it to each of the joints to cover them with mud. This will ensure that your jointing tape is embedded properly.

Remove any excess compound, then wait for it to dry.

Step 7 – Remove rough edges

With a 200mm taping knife, remove any rough edges around the outside of the joint so that the surface of the plasterboard is smooth.

Step 8 – Add second coat of compound

Apply a second coat of jointing compound, feathering out the edges to blend them into the main sheet of plasterboard.

Leave the compound to dry.

Step 9 – Sand

Once again, remove rough edges with your taping knife then use a hand sander to remove any excess compound from the surface of the plasterboard.

Step 10 – Apply finishing coat

With a trowel, apply a finishing coat of compound to the entire area.

Leave to dry for 24 hours, then sand to prepare for painting.

Step 11 – Remove dust then paint

Use a brush to remove any dust.

Once the plasterboard is completely smooth, paint the area to blend in the new patch with the rest of the wall.