Standing water on a flat roof — Long Beach, California

If water is still pooling on your flat roof 48 hours after the last rain, you have a ponding problem. Flat roofs are designed with a slight slope to drain, but sagging decking, clogged internal drains, or shifted insulation can create low spots where water sits. Prolonged ponding accelerates membrane deterioration, adds hundreds of pounds of dead load to the structure, and eventually causes leaks. A roofer can identify the cause — whether it's a drainage issue, structural deflection, or membrane failure — and restore proper drainage with tapered insulation, additional drains, or membrane repair.