FA Exhibit DET-008

Valley: 26-ga metal over D3909 cap sheet, layered

A code-text layer stack and an intentionally not-to-scale valley section show corrosion-resistant metal valley flashing over a mineral-surfaced nonperforated ASTM D3909 cap sheet over combustible decking. A separate strip drawn at ten pixels per inch shows the cap sheet's minimum thirty-six-inch width and continuation for the full valley length. — FA Exhibit DET-008. Valley: 26-gage metal over ASTM D3909 cap sheet. AFTER 2023 OREGON RESIDENTIAL SPECIALTY CODE R327.3 · WILDFIRE HAZARD MITIGATION-2. Illustrative — not a construction document. Verify with your building official. CC BY 4.0.

Technical review: Grayson Graham. Last verified 2026-08-25. JSON

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<img src="https://fireapproved.com/diagrams/det-008-valley-metal-over-d3909.svg" alt="A code-text layer stack and an intentionally not-to-scale valley section show corrosion-resistant metal valley flashing over a mineral-surfaced nonperforated ASTM D3909 cap sheet over combustible decking. A separate strip drawn at ten pixels per inch shows the cap sheet's minimum thirty-six-inch width and continuation for the full valley length." />

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