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.
(..) is / tons per square inch. These windows are nine inches thick. lf they go, it's sayonara in two microseconds. All right. Enough of that bullshit. Put her down on the roof of the officers' quarters. Sure. Okay, Mir . We've landed on the grand staircase. You guys set to launch ? (..)1997 Titanic