How many inspiring episodes have you seen where a quick addition of crown molding classes up a room? But heed a word of caution here: “No walls in a house are perfectly straight, not even in new houses,” says Sadura. And no amount of caulk will smooth over these imperfections, either. In fact, Sadura says experts who do molding use various techniques such as scribing, which is painstakingly shaping your material with tools so it fits flush, to ensure your moldings are aligned and stay that way. All in all, it’s not for the amateur DIYer.