Wondering if your lush urban garden is overloading your deck? It's a crucial safety consideration. First, identify your deck's design load capacity. Most residential decks are built to hold 40-50 pounds per square foot (psf). This includes furniture, people, and your planters. To calculate the weight of your planter boxes, consider the weight of the empty container, saturated soil (which is surprisingly heavy—about 75-100 lbs per cubic foot), plants, and water. Add this total weight and divide by the box's footprint area to get its psf load.
Next, conduct a visual inspection. Look for warning signs like excessive bouncing, sagging, loose railings or posts, cracked joist hangers, or rotting wood. These indicate stress. Always distribute weight evenly and place heavier planters near load-bearing walls or support posts, not in the center of a span. When in doubt, consult a structural engineer or qualified contractor for a professional assessment. They can evaluate your deck's actual condition and capacity. Prioritizing this check ensures your green oasis remains a safe, enjoyable space for years to come.