build up to
build up to (something)
1. To reach something gradually. I know you're building up to your point, but you're also putting your audience to sleep. You can't just walk into the gym and grab the 50-pound weights—you need to build up to that!
2. To become or develop into something gradually. The issues that you're trying to ignore in your relationship will build up to serious problems in time.
Farlex Dictionary of Idioms. © 2015 Farlex, Inc, all rights reserved.
build up to something
1. [for a person] to lead up to something or advance to doing or saying something. I can tell you are building up to something. What is it?
2. [for a situation] to develop into something. The argument is building up to something unpleasant.
McGraw-Hill Dictionary of American Idioms and Phrasal Verbs. © 2002 by The McGraw-Hill Companies, Inc.