- Joint tape is a strong, cross-fibered tape used with joint compound to seal, secure and smooth the seams between drywall boards. Typically 2 to 3 inches wide, joint tape comes in three basic varieties: paper tape, fiberglass mesh tape and water-activated adhesive tape. Paper tape must be adhered to the joint with an underlayer of joint compound. Mesh tape has adhesive on one side and is pressed onto the drywall by hand or with a taping knife. Water-activated adhesive tape is dipped in clean water and applied over the joint by hand. As it dries, it adheres to the drywall. Joint tape is considered non-toxic, but sanding of tape and compound can irritate the eyes or respiratory system. Wear goggles and a dust mask when sanding.
- Apply fiberglass mesh tape directly to the drywall. Begin at the ceiling line for vertically hung drywall or at the left or right wall edge for horizontally hung boards. Since this is a dry application, work straight from the roll. Pull 12 to 18 inches of tape from the roll, line up the leading edge of the tape and stick the adhesive side to the drywall. Center the remaining length of tape over the joint and press to the wall, then smooth over it using your hand or a taping knife (See Resources section). Pull another length of tape from the roll and repeat process until the entire joint is covered.
- Measure a length of joint tape for the seam. Cut to fit the entire length of the drywall or work in shorter, more manageable lengths. Use a dish or bucket of clean water and completely submerge the length of tape. This activates the adhesive. Center tape over joint and press tape into the gap with your hand. Then smooth the edges of the tape with your hand, adhering it securely to the surrounding drywall. Check that there are no gaps or bubbles in the tape. Let dry completely. If bubbles remain after drying, blot with a damp sponge, smooth with hand and let dry.
- Cut a workable length of paper tape. Use a 5- to 6-inch taping knife to spread joint compound generously over the seam and fill the gap between the two pieces of wallboard. Smooth the compound over the wallboard joint in a stripe that is wider than the joint tape. Work fast, as joint compound dries quickly. Continually wipe the edges of the joint knife to keep compound from hardening on the surface. Starting at the ceiling line for vertically hung wallboard, center the paper tape over the joint and press it into the wet compound. Use the joint knife to help embed the tape in the compound and smooth out any wrinkles or bubbles. Let dry overnight.
- Use joint tape on inside corners of a room to seal gaps between the wallboard. All three styles of tape can be folded down the center to create a crease. Some joint tapes come with a pre-made crease that makes alignment in the corner easy. Press center of tape into corner first, then smooth tape edges onto walls, working down one side and then the other.
- All styles of joint tape are then covered with two to three more layers of joint compound. Each layer must dry overnight to set completely. The ends of each layer are feathered out, with the subsequent layer extending 2 inches farther out on either side before feathering. Joint compound shrinks and cracks as it dries, requiring multiple layers to secure the joint. The joint tape acts as a sturdy, bonded connection to hold the compound in place and prevent cracking, shifting, splitting or visible gaps in the drywall. The final layer of compound is sanded lightly to blend smoothly into the surrounding drywall and create a uniform wall appearance.
