Mechanism in plain language
How blockage, slope, capacity and roof valleys concentrate water at specific edges. In this path, the relevant mechanism is concentrated runoff can exceed drainage capacity and drive water toward vulnerable enclosure or below-grade interfaces A mechanism is only useful when it connects a trigger, a route and an observable result.
What must be true for the mechanism to fit
The event timing must agree with the transport or movement time, the geometry must offer a plausible route and the strongest changes should occur where the mechanism predicts—not merely where the finish is easiest to see.
Follow energy, water, air, load or material movement
Trace the pathway through gutter, downspout, roof edge, patio, driveway, grade or foundation perimeter. Mark where the driving force begins, which layer or connection carries it and where the visible symptom finally appears. A source and an exit point are often different places.
Lookalikes that use a different pathway
Compare blocked gutter, short discharge, adverse grade, surface drain failure, saturated soil and concealed supply leakage. For each alternative, write one observation that would strengthen it and one that would make it less likely. Avoid treating a familiar mechanism as the default answer.
Safe evidence that improves the model
- Observe runoff during a safe rain event
- Map where each downspout discharges
- Compare ponding duration and interior symptoms after similar storms
- Repeat one controllable trigger at a time where safe and preserve an unaffected reference.
- Record instrument placement and operating state; an indicative reading is not a hidden-condition diagnosis.
Limits and professional boundary
Avoid ladders, roofs, flooded electrical areas, unstable excavations and changes that direct water onto neighboring property. Significant foundation movement needs qualified review. The source set for this guide includes 4 official records selected for this path. They provide general technical and safety context; they do not determine the condition of a particular house.
Primary references for this topic family
These references ground the general building-science or safety context. They do not diagnose a specific house, replace local requirements or certify a repair.
