In drywall installation, what is the purpose of using a joint tape?

In drywall installation, the use of joint tape serves the primary purpose of reinforcing joints between the sheets of drywall. When drywall panels are butted together, the seams need to be finished to create a smooth, continuous surface that can be painted or otherwise treated. Joint tape, typically made of paper or fiberglass mesh, is applied over these seams before a joint compound (often called mud) is used.

The tape adheres to the joint compound, which is then applied over the tape to create a smooth surface. This reinforcement is crucial because it helps to prevent cracking or separation of the joint over time due to movement or settling of the structure. By providing this extra strength and stability, joint tape ensures a durable finish that can withstand the natural expansion and contraction that occurs in buildings.

Other options like providing water resistance or connecting insulation do not align with the primary role of joint tape in drywall installation. Similarly, while sealing edges may be a concern in different contexts, it is not the main function of joint tape. The focus remains on reinforcing the seams to ensure a strong, lasting finish.