How to Tape Plasterboard Joints With Paper Tape
Paper tape jointing is the traditional method for finishing plasterboard joints and the preferred choice for many professionals. It creates a smooth, uniform wall by covering over the joints between plasterboards to deliver a clean finish under paint. Here's how to tape, fill, and finish plasterboard joints using the paper tape method.
Why use paper plasterboard tape?
Paper plasterboard jointing tape is pre-creased down the centre, which makes it ideal for both flat joints and internal corners. Because paper plasterboard tape is bedded into wet filler rather than stuck on with adhesive, it adheres into the joint compound itself, creating a strong bond and integrating into the surface to add strength and resist cracking.
Using paper tape takes a little more skill to apply than self-adhesive scrim. The tape needs to be properly bedded with no air bubbles or dry spots underneath, otherwise it can lift and the joint may fail.
Step 1: Tape - Bed the Paper Tape
Start by checking the plasterboard joints. The boards should be tightly butted together with no gaps wider than 2 to 3mm. If there are larger gaps, fill them first and allow them to set before taping. Some professionals cut the edges of butt joints to allow the joint filler to penetrate the gap. The 45-degree angled cuts also increase the surface area to be filled. Tapered boards already provide the depth required to fill the space between the boards.
Using a filling knife, apply a thin, even bed of joint filler along the length of the joint. The bed coat should be roughly 50 to 75mm wide and just thick enough to fully cover the joint. You are creating a bed for the tape to sit in. Cut the paper tape to length and press it into the wet filler, centring it over the joint. Using a taping knife, draw firmly along the tape from the centre downward, then upward, pressing the tape into the filler and squeezing out any excess compound from underneath. Work out any air bubbles or wrinkles as you go. The tape should sit flat against the board with a thin, even layer of filler behind it and no dry spots.
Step 2: Fill - Build the Joint
Once the tape is fully embedded in the filler, apply a second coat of filler over the top. This coat covers the paper tape, ensures it is fully embedded, and builds the joint up to a level, even surface that disguises the tape. Use a taping knife or a broader knife than you used for the bed coat. A 150mm or 200mm knife works well here. Feather the edges out to blend the joint into the surrounding board.
The key is to create a gentle taper from the high point over the joint down to the flat board surface. This is what makes the joint invisible under paint. A joint that is built too narrow can show as a shadow, while a joint that is tapered too steeply can appear as a raised line.
Apply the filler in smooth, even passes. Avoid going back over the same area repeatedly, as overworking creates ridges and can pull filler off the surface. One or two confident passes per section are usually enough.
Allow the filler to set fully before moving on to the finishing stage.
Step 3: Finish – Skim to a Smooth Surface
Once the fill coat has set, lightly sand with fine-grit sandpaper (P180) to remove any ridges or high spots. Do not sand aggressively - you are smoothing, not reshaping. Be careful not to sand through to expose the paper.
Apply a final thin coat of your chosen finish product over the joint and feather it out well beyond the edges of the fill coat. This finish coat is what blends the joint seamlessly into the surrounding plasterboard. Use a broad knife and work in long, even strokes.
For the best result, feather the finish coat out at least 50-75mm beyond the fill coat on each side. The wider the taper, the more invisible the joint.
Allow to dry completely, then lightly sand with fine-grit sandpaper. The joint is now ready for decoration.