A leak that appears only when rain is driven hard against one side of a Florida house is a useful clue. Ordinary vertical rainfall and wind-driven rain do not load the building envelope the same way; wind can push water against windows, joints, soffits, roof-to-wall intersections and cracks that stay dry in routine weather.
Why Storm-Only Leaks Are Different
If a wall stays dry during ordinary rain but leaks during tropical storms, squalls or hurricanes, the failure may depend on wind direction and pressure. Water can be driven into openings that normally shed rain, and the pressure difference across a window or wall assembly can help move water inward.
Common Entry Points
The visible wet spot is not necessarily the entry point. Water may travel along framing, sheathing, masonry surfaces or the back of stucco before it becomes visible indoors.
- Window and door perimeter flashing or sealant transitions.
- Roof-to-wall intersections, kick-out flashing and parapet conditions.
- Soffit, fascia and roof-edge details exposed to wind-driven rain.
- Cracks, penetrations and joints in stucco or masonry.
- Failed or poorly integrated water-resistive barriers on framed walls.
Why a Hose Test Can Mislead
A garden hose can sometimes reproduce a leak, but spraying everything at once may tell you only that water can enter somewhere. Professional field testing isolates areas and, when appropriate, combines calibrated water spray with a pressure difference. ASTM E1105 is one standard used for field determination of water penetration through installed windows, doors and related assemblies.
A Better Diagnostic Sequence
Start with the storm pattern and work outward from the interior evidence. Note wind direction, elevation, nearby windows, roof intersections and wall penetrations. Inspect from the highest plausible entry point downward. If testing is needed, isolate one component at a time rather than flooding the entire wall.
- Photograph the interior wet area immediately after the event.
- Record which direction the storm was blowing.
- Check the roof and wall above the symptom, not only the stain itself.
- Avoid sealing random exterior joints until the intended drainage paths are understood.
Florida Code Check
The 2023 Florida Building Code requires the exterior wall envelope to be detailed as a system, including flashing, intersections, drainage, water-resistive membranes and openings. That is why a storm-only leak should not automatically be treated as a paint problem.