When caulking interior trim the caulk is usually wet wiped to remove the excess and to give a clean look. If too much is removed in the wiping process it will result in a very thin bead that will readily crack and split. ... If the caulk is put on with too small of a bead it is more susceptible to cracking and splitting.

Why does caulking crack after drying?

Before using caulk, make sure it indicates paintable on the packaging. Applying paint over a partially dried bead of caulk, the paint dries first, forming a film. As the caulk dries, it shrinks and causes the paint film to stretch and crack.

Why does silicone caulk crack?

Many times, inadequate or improper surface preparation causes the caulk joint to crack or separate from the surfaces of the joint. Surface preparation is not complicated, but it can be tedious to perform correctly.