(Mishnah): If one gave something to a craftsman to fix, and the craftsman ruined it, he is liable;

If he gave a chest, box or tower to a carpenter, and he ruined it, he is liable;

If a builder was hired to dissemble a wall, and he broke it or damaged the rocks, he is liable;

If he was dissembling from one side, and it fell from the other side, he is exempt;

If it fell due to the blow, he is liable.

(Gemara - Rav Huna): [The Reisha] is when he banged the last nail in, in order to acquire it (i.e. he was given a Kli, therefore he pays for a Kli. He holds that if he was given wood, when he made it a Kli, the craftsman acquired it, so he would owe only the value of the wood.)