A general understanding of the different styles of architecture and what the desired effect of each style is useful. If you are somewhat familiar with each style, the you will know what to look for [ceilings, flying buttresses, types of arches, ...] Find a book on the history of architecture.
Is this like saying, "Do you have to understand women to photograph them"?
Originally Posted by Jeephoto
In that case, there wouldn't be many such photos. :p
don't worry if you have no formal training
or "understanding" or architecture ...
you know what it does for you and that is the most important thing.
once you get a formal education in anything you have all that excess baggage to
carry around + think about.
photograph things from the "gut" instead of the book
( and have fun ! )