This architectural drawing is Reinforcement section of balcony. The easiest and most economical way to add a balcony would be to install outboard corner columns (on individual square column footings). They could be either RCC or structural steel. Steel columns would be more economical. On both types of balconies, railings are added after initial construction and are either embedded into the concrete of the balcony or surface mounted. For more details and information download the drawing file.