Forensic water intrusion diagnosis · Lesson 2 of 4

Forensic water intrusion diagnosis: materials, standards and design constraints

What each standard says it covers and where it stops; how much of a roof each survey method sees; why lapped joints and splice plates matter; gap widths from AFS, Drexel and BSC; and the moisture thresholds for wood.

You will be able to: Choose a candidate method from its stated scope, tell guides from test methods and practices, recognize that no scope read here names roof-edge metal, and use sourced numbers for joints, gaps and wood moisture.

11 min · 12 slides · 8 questions

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Slide 1 of 12

Read the title, then the scope

By their titles, ASTM E2128, D5957 and D7877 are guides, E1105 is a test method, and C1153, E1186 and E1188 are practices.

A document is used where its own scope fits. Cite its designation and edition year, such as E2128-26 or C1153-23.

ASTM's page for E1105-15 (2023) marks it historical and lists E1105-26 as the active edition.

Sources

Videos for this lesson

What this video shows: A live field demonstration of ASTM E783 air and E1105 water tests on a window unit: the interior test chamber and the spray rack on the outside. A window, not roof-edge metal.

Video: Field Test Demonstration at FGIA 2022 Fall Conference by FGIAVideoChannel, on YouTube. Chosen from the video's published description.

What this video shows: An equipment maker explains electronic leak detection on existing membrane roofs and why infrared and capacitance typically cannot pinpoint the source. One maker's view; it does not apply to metal flashing.

Video: Forensic Electronic Leak Detection (ELD) Testing for Existing Roofs with Active Leaks by Detec Systems, on YouTube. Chosen from the video's published description.

What this video shows: A long talk on drainage physics in walls with lab drip-edge rigs; its description says small gaps can drain plenty of water and bigger gaps exist for tolerance and ventilation. About 100 minutes; about wall drainage gaps.

Video: Drain, Drain Go Away (John Straube, 2026 Westford Symposium) by BuildingScience-com Corporation, on YouTube. Chosen from the video's published description.

Glossary

Guide, test method and practice: ASTM titles say which kind a document is: E2128, D5957 and D7877 are titled guides, E1105 is titled a test method, and C1153, E1186 and E1188 are titled practices.
Wet insulation survey: ASTM C1153 covers locating wet insulation in roofing systems with infrared imaging at night. Locating wet insulation is not the same as finding where the water got in.
Electronic leak detection: ASTM D7877 describes electrical conductance methods for locating leaks in exposed or covered roofing and waterproofing membranes. Detec Systems, an equipment maker, says it needs trapped water to reach a conductive deck.
Fiber saturation point: USDA Forest Products Laboratory: wood moisture content, averaging 30 percent, above which serious decay can occur. Water vapor in humid air alone will not wet wood enough for significant decay.
Splice plate: In Drexel's guides, a piece placed at the joint between two lengths of edge metal; the Drip Edge guide says there should be one at every joint.
Capillary break: In Building Science Corporation's wall guidance, a drainage gap that acts as a capillary break; BSC says it should be in the order of 1/4 in (6 mm) wide, since that is approximately the size of a gap that can be spanned by water.
Drying window: EPA advises drying water-damaged areas and items within 24 to 48 hours to prevent mold growth.