The invention relates to a support unit provided in the glazing rebate of a façade or a transparent roof for panes of insulating glass (6) or infill panels, whose external edges lie on seals (10) of cover mouldings (9) and whose edges on the side of the building lie on seals (5) of mullion sections (1) or rail sections (2), said rail sections (2) being provided with a mounting section (3). The support unit comprises a mounting section (3), which is at least partially provided with a glass support plate (12) that extends centrally through the rebate region and can be connected to the rail section (2). The glass support plate (12) is preferably introduced and fixed into a recess (13) of the mounting section (3). The inventive support unit permits the rail section to bear increased loads and can be mounted easily and cost-effectively.