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.
(..) BOTH: (SINGING) Five more minutes... SARAH: No! - (GLASS SHATTERS) - (CAT YOWLS) That's our chimney! You're gonna destroy the whole roof? Mom, we have to replace the chimney with a slide for when the storks deliver my baby brother. What he said. (..)2016 Storks