"Hit the roof" (letteralmente "colpire il tetto") significa arrabbiarsi molto o meglio "andare su tutte le furie".

Es. I told Jason about seeing his girlfriend kissing another man and he really hit the roof.

My brother hit the roof when I told him that I'd crashed his car

In un inglese piu' formale diremmo "to explode with anger"

es. When the ambassador realized his briefcase had been stolen, he exploded with anger as all his confidential documents were in there.