Not necessarily. It depends on what you wish to do. It will temporarily seal a portal so that nothing else may come through... it will increase the strength of a threshold as long as you hold it, such as in a doorway, or temporarily create a threshold in something like a hallway, an interior space... and, of course, in the case of our drain. This does not mean they cannot advance until that point... but it may give us the few seconds of time we need.

While they cannot cross that threshold, however, they can still possibly influence you - hence why it is best to be used as an engraving or a drawing upon doors. But it will work in a pinch.