How to Finish Wallboard Seams

There are two different ways to finish wallboard seams. One is to use paper tape, which must be applied over joint compound and smoothed and sanded, and the other is to use adhesive backed mesh tape, which is then covered with joint compound. For ease of use, adhesive backed mesh tape is recommended and will be addressed here. Most supplies for this project can be purchased at your local home improvement store. Allow a couple of days for completion.

Things You'll Need

• Adhesive mesh drywall tape
• Scissors
• Joint compound
• 4-inch joint finishing knife
• 10-inch joint finishing knife
• 80-grit sandpaper
• 120-grit sandpaper
• Sanding block
• Clean rag
• Wood block or trowel
• Water
• Shop vac or household vacuum with wand

Instructions

Process

1. Cut a length of mesh adhesive-backed tape to fit and center it over the wallboard seam, pressing down.

2. Use the 4-inch finishing knife to apply a coat of premixed joint compound over the seam. Hold the knife at a 45-degree angle as you work your way from one end of the seam to the other.

3. Allow to dry completely.

4. Sand with 80-grit sandpaper on a sanding block, making sure the seam has an even surface.

5. Apply a second coat of joint compound using the 10-inch finishing knife. Make sure to extend coverage beyond the seam slightly feathering and thinning out the application so it blends in.

6. Allow to dry for at least 24 hours.

7. Sand with 120-grit sandpaper on a block until smooth. Vacuum away dust and wipe with a clean rag.

8. Put a small amount of joint compound on your wood block or trowel and thin slightly with a small amount of water.

9. Apply a final coat of the thinned-out compound to the seam, feathering out two inches beyond the second coat for a disappearing seam. Allow to dry completely.

10. Sand a final time with 120-grit sandpaper. Remove dust with clean rag.

References

• Bob Vila