When sourcing fiberglass columns, you must distinguish between FRP (Fiberglass Reinforced Plastic) and GFRC (Glass Fiber Reinforced Concrete). For structural integrity, ensure the columns have a load-bearing capacity verified by engineering reports; many fiberglass columns are decorative 'sleeves' and require an internal support post. Key specs include wall thickness (typically 1/4" to 3/8"), flame spread rating (Class A per ASTM E84), and UV-inhibitor additives in the gel coat to prevent yellowing and chalking over time.