How to conceal tapered plasterboard joints with joint tape

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Their shallow recess provides a space for the jointing tape and compound to sit, so they are easier to disguise than butt joints.

You will also need a set of taping knives, some jointing compound and a sponge.

Step 1 – Cover screws

Before filling the joint, run a knife along its length to check for any raised plasterboard screws.

If necessary, screw the fasteners further into the plasterboard so that they are below its surface. Then cover each screw head with jointing compound.

Step 2 – Apply base coat, if necessary

Scrim tape can be stuck directly onto the joint, but if you are using paper tape, you will need to apply a base coat of compound to the joint to attach the tape to the plasterboard.

Use a 150mm (6″) taping knife to spread the compound in a thin layer so it is wide enough to accommodate the width of your jointing tape.

Step 3 – Apply tape

Centre the width of your tape over the seam of the plasterboard and unroll it as you move along the joint.

Run your knife along the length of the tape, pressing down firmly to secure it to the wall.

Step 4 – Cut tape

When you get to the end of the joint, use a 150mm (6″) taping knife to cut the tape to length.

Holding the end of the tape taut, pull it against the blade of the knife to tear it away from the rest of the roll.

Step 5 – Cover tape with compound

Load your 150mm taping knife with jointing compound and apply the compound to the tape.

The compound should not only cover the width of the jointing tape, but the plasterboard 50-100mm (2″-4″) on either side of the tape.

Scrape away excess mud, then wait for the compound to dry.

Step 6 – Apply second layer of compound

When the first layer of jointing compound has dried, it is time to add a second coat to further reinforce the joint.

With your 200mm (8″) taping knife, spread the jointing compound over the plasterboard to widen the area covered. Smooth the compound so that it is as flush to the face of the board as possible.

Wait for the compound to set.

Step 7 – Apply third layer and feather edges

Scrape away any high spots then apply a third layer using the 300mm (12″) taping knife.

Feather out the edges by holding just the top edge of the knife tight to the wall. Continue to do this until the compound covers an area at least 300mm (12″) wide.

Step 8 – Remove irregularities

After the third coat has dried, use a damp sponge to blend the edges on either side of the seam into the surface of the plasterboard and smooth any imperfections.

This will ensure that the compound is as thin and smooth as possible.