How to tape and finish drywall joints

1. Tools and materials

You need joint compound (ready-mixed or setting type), paper or fiberglass mesh tape, a 15 cm knife, a 25–30 cm knife, a mud pan, corner tools or beads, and fine sanding mesh or a sanding sponge.

2. Tape the joints

Fill the joint with a layer of compound, press paper tape into it with the knife and squeeze out the excess, leaving a thin layer under the tape. With mesh tape, apply the tape first and then the compound. Tapered edges make a shallow channel that hides the tape.

3. Corners and screws

Fold paper tape for inside corners and bed it in compound, finishing one side at a time. Protect outside corners with metal or paper-faced corner bead. Cover every screw head with a thin swipe of compound in each coat.

4. Build up thin coats

Apply two or three more coats, each wider than the last, feathering the edges to nothing. Let each coat dry fully. Thin coats dry faster and need much less sanding than one thick coat.

5. Sand and prime

Sand lightly with fine mesh, holding a light at a low angle to spot ridges and hollows. Wear a dust mask. Prime the whole wall before painting, as compound and paper absorb paint differently. See How to build a drywall partition: step-by-step guide and How to paint a wall: a step-by-step guide.

Common mistakes

• Thick coats of compound that crack and need heavy sanding.
• Air bubbles under paper tape from too little compound.
• Sanding through the paper face of the board.
• Skipping primer, so joints show through the paint.
• Sinking screws too deep, tearing the paper.

Frequently asked questions

Sources

• Gypsum Association — GA-216 Application and Finishing of Gypsum Panel Products
• Wikipedia — Joint compound