Shabbos 13:2

If a person ties two loops to the heddles or the warp of a loom, in a sifter or a sieve, or in a basket, he is liable. A person is liable for sewing two stitches, or for tearing in order to sew two stitches.

Shabbos 13:3

If a person rips something in his anger or in distress over a death, or if he destroys something, he is exempt. If a person demolishes something for the purpose of building, he is liable. The amount that incurs liability would be based on the amount one is liable for the analogous building activity.