Europe, and indeed the rest of the world, is experiencing record heavy rainfalls. And the frequency with which they are occurring has also increased exponentially. This poses many challenges to building and home owners, not the least of which is safe roof drainage. Traditional gravity drainage is fast-becoming a thing of the past. Today, many large industrial, commercial and retail buildings use siphonic drainage to quickly and efficiently discharge the rainwater from their rooftops. And residential buildings are beginning to follow suit.