Water is pooling on your flat roof. Again. Or worse, it is coming through the ceiling. Flat roofs leak differently than sloped roofs, and fixing them requires understanding how these systems work.
Finding Flat Roof Leaks
Flat roofs are not actually flat. They have slight slope to direct water toward drains or edges. When that slope fails or drains clog, water ponds. Ponding water eventually finds a way through.
The leak source is usually one of these:
Seams where membrane sections join together. These get heat-welded, glued, or taped depending on the system. Over time, seams can separate. Temperature cycles expand and contract the membrane, stressing joints repeatedly.
Penetrations where pipes, vents, HVAC curbs, and drains pass through the membrane. Each penetration requires careful sealing. The seals can fail from age, UV exposure, or movement.
Physical damage from foot traffic, dropped tools, wind-blown debris, or equipment dragged across the surface. Even small punctures let water in.
Membrane failure from age, UV degradation, or chemical exposure. The material itself breaks down over time.
Locating the entry point can be tricky. Water travels along the membrane, sometimes pooling in insulation before finding a path through the deck. The wet spot on your ceiling might be far from the actual roof penetration.
Repair Options
Patching works for isolated damage. A skilled contractor can clean the area, apply primer if needed, and bond a patch of matching membrane material. Seam repairs use the same techniques - cleaning, priming, heat-welding or adhesive depending on membrane type.
Coating makes sense when you have widespread surface deterioration but the membrane is structurally sound. A silicone or acrylic coating seals hairline cracks and provides UV protection. This is not a fix for active leaks but can prevent future ones.
Replacement becomes necessary when the membrane is extensively damaged, insulation is saturated, or the roof has been patched repeatedly and keeps failing. At some point, more patches just delay the inevitable.
Address drainage whatever you do. Fixing leaks without fixing ponding water is temporary at best.
Peak Builders specializes in flat roof systems across San Diego. We diagnose problems accurately and recommend solutions that make sense for your specific situation.
