backRoom RequiRemeNT: Backroom is defined as the distance needed from the opening back into the garage to allow the door to open fully. weather Seal (may Not be included): Cut or trim the weather seal (if necessary) to the header and jambs. Align the header seal with the inside edge of the header and temporarily secure it to the header with equally spaced nails. Next, fit the jamb seals up tight against the header seal and flush with the inside edge of the jamb. Temporarily secure the jamb seals