What type of masonry is not commonly used for balcony columns?

Lightweight plastics are not commonly used for balcony columns, primarily due to their structural properties and load-bearing capabilities. Balcony columns need to support significant weight, including the weight of the balcony itself and any additional loads, such as occupants and furniture. Traditional materials like brick, stone, and concrete blocks possess the necessary strength and durability required for these applications, making them ideal choices for structural elements like columns.

In contrast, lightweight plastics, while beneficial for specific applications where weight reduction is advantageous and load requirements are minimal, do not offer the compressive strength or stability needed for supporting a balcony. Plastics can also be less resistant to environmental factors, such as UV exposure, which can weaken them over time if they are not specifically engineered for structural use. Therefore, while they may be used in some decorative or non-structural applications, they are not suitable for the critical function of supporting balcony columns.