The mullion-transom facade is the most widespread form of curtain wall in commercial construction. Vertical aluminium profiles (mullions) are anchored to the structural frame and receive horizontal transoms. The resulting bays are filled with insulating glass, opaque panels, or ventilation units. EPDM gaskets and pressure plates ensure airtightness and watertightness. Thermally broken profiles reduce thermal bridges. Structurally, the mullion cross-section carries wind loads while transoms transfer the dead weight of infill elements. Fire protection requirements are met through dedicated fire-rated systems or intumescent inserts. The system offers design flexibility in grid dimensions and surface finishes and is widely used for office buildings, shopping centres, and public facilities.