A door leaf or casing frame for windows, doors or the like and a process preparing the same. The door leaf or casing frame is assembled by joining hollow sections (3-6; 7-10) and T-pieces with the use of a binder; the hollow sections are particularly of Duroplastic with longitudinally extending reinforcing fibers. A joint plate is disposed in the connecting joints or mitre joints (15, 15a) of the frame corners, said plate having through channels for the binder, T-pieces being integrated with the joint plate. In the production of the frame a glue or adhesive composition is sprayed through the channels of the joint plates into the gap in the area of the corresponding corner.