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Forensic water intrusion diagnosis · Lesson 3 of 4

Forensic water intrusion diagnosis: methods and worked application

The step-by-step sequence; finding the roof point; the hypothesis table; checking a reported storm against NOAA depths; counting joints on a metal run; one-component water checks; non-destructive methods first; and what to record.

You will be able to: Apply a documented sequence to a realistic leak: locate the roof point from an interior stain, list candidates with a test that could disprove each, check the reported storm against NOAA depths, count the joints on a run, and record assumptions, units and evidence.

9 min · 12 slides · 5 questions

All lessons in this module
Slide 1 of 12

The sequence, step by step

The course sequence: intake and history, survey and photographs, locate the roof point, list candidates with disproving tests, non-destructive checks, one-component water checks, exploratory opening, confirm, correct, retest, report.

The figure tags steps from a cited document and marks the rest as the method taught here. ASTM E2128 is a wall guide, used here by analogy.

A documented diagnosis, step by stepFlow chart: intake and history; condition survey and photographs; locate the roof point from the interior symptom; list candidates with a disproving test; non-destructive checks; a decision on whether the source is outside the wall or roof system or is condensation; one-component water check where a method exists; exploratory opening; a decision on whether the cause is shown by evidence, looping back to the candidate list if not; correct with the warranty first; retest; report with limits.A documented diagnosisIntake and historyCondition surveyand photographsLocate the roof pointfrom the stainList candidates, eachwith a disproving testNon-destructive checksOutside the system,or condensation?One-component watercheck, where a method existsExploratory opening,then patch itCause shownby evidence?Correct, warranty firstRetest the same wayReport with limitsRefer onor splityesnoFrom a cited documentMethod taught here, not a standard

Flow chart: intake and history; condition survey and photographs; locate the roof point from the interior symptom; list candidates with a disproving test; non-destructive checks; a decision on whether the source is outside the wall or roof system or is condensation; one-component water check where a method exists; exploratory opening; a decision on whether the cause is shown by evidence, looping back to the candidate list if not; correct with the warranty first; retest; report with limits.

Steps tagged "cited" come from a document named on the slides; the others are the method taught here, not a standard.

Sources

Glossary

Reference point
A fixed place on the roof from which interior leak damage is located by measuring; UFC 3-110-03 says to locate the interior damage by measuring from a reference point on the roof.
Hypothesis table
This course's working name for a list of candidate entry points, each with a test that could show it is not the cause. A candidate with no such test is a guess.
Recurrence interval (ARI)
The column heading NOAA Atlas 14 uses for the years in its precipitation table; the table lists the depth of rain for a stated duration at each interval, for example 1 year and 100 years.
Exploratory opening
A cut or removal to look at a concealed condition. ASTM E2128 warns that investigative techniques may be intrusive, disruptive or destructive, so the opening and its patch are planned first.
Evidence log
The record of dates, weather, locations, photographs, measurements, samples, tests and what was disturbed. ASTM E1188 covers collecting and preserving such information for incidents that may be the subject of litigation.