We don't have much money, but at least we 'have a roof over our heads'. [=at least we have somewhere to live]
You'll do what I say as long as you're living 'under my roof'. [=as long as you are living in my house]
We hope to have sales and service 'under one roof' [=at the same location] in the near future.
(..) just came off the building. What the fuck? Fuck. What do you mean, off the building? - Something came off the fucking roof. - It's a fucking body. We can't get a visual. Want us to get out? We gotta get on foot if you want me to get up on this thing. - Where were you? - What happened? You're fucking late! Get in the van! What do you mean, off the roof? What's going on? I came to meet you. - What the fuck...? - Get in the van! I got four armed men right out front. You want us to pursue? (..)2006 The Departed