Why do you need to use tape with joint compound?

Question

Why do you need to use tape with joint compound?

Answer 1

Because the compound shrinks a little when it dries and will leave a gap. Tape stops this from happening. As well as the above reason.

Answer 2

because if you don't there is no supporting connection between the two pieces of drywall and the slightest vibration will cause it to crack.

Answer 3

In addition to the excellent answers above, there is also an element of spanning the gap in such a way that helps eliminte the telltale lines that you may see after the room is painted. If you cover the tape completely, you will be forced to span a wider area than the original crack, and in doing so, you will "fan out" the mud and camoflage the gap better... Hope that clarifies things for you.

Answer 4

In addition to all other answers.  I find that mesh tape is so much easier to use than paper. The seams are clean and smooth.

Answer 5

If you don't, the 'mud' will shrink & reveal the gap again.

Also walls expand & contract over time & with temperature.