Sheet Metal (C-43) · Lesson 6 of 8

Metal Roof Panels: Minimum Slope, Materials, and Fasteners (CBC 1507.4)

"Metal Roof Panels: Minimum Slope, Materials, and Fasteners (CBC 1507.4)" is lesson 6 of 8 in the Sheet Metal (C-43) Learning Hub. It opens with "Which Code Section Applies" and works through 5 short steps, then a worked example you can check yourself against.

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Steps in this lesson

  1. Which Code Section Applies
  2. Minimum Slope Depends on the Seam
  3. Material Standards: Table 1507.4.3
  4. Fasteners: Match the Metal
  5. Flashing, Crickets, and Metal Shingle Valleys

The worked example in the course applies this lesson to a realistic job in 5 steps, from "Convert the pitch to percent" through "Material and fasteners".

What you'll be able to do

  • Explain the main idea of "Metal Roof Panels: Minimum Slope, Materials, and Fasteners (CBC 1507.4)" in plain language you can use on the exam.
  • Apply this step with confidence: "Material Standards: Table 1507.4.3".
  • Apply this step with confidence: "Fasteners: Match the Metal".
  • Apply this step with confidence: "Flashing, Crickets, and Metal Shingle Valleys".
  • Test yourself on the worked example and the quick-check quiz inside the classroom.
Metal Roof Panels: Slope and MaterialRoof pitched 2 in 12, checked three waysrise 2 in per 12 in run = 16.7%12 in run2 inMinimum slope required (percent)Standing seam2%Lapped + sealant4%Lapped, no sealant25%this roof: 16.7%Slope and material checksRoof pitch 2:12 = 2 / 12 = 16.7%Lapped, no sealant: 3:12 (25%): FAILLapped + sealant: 1/2:12 (4%): PASSStanding seam: 1/4:12 (2%): PASSTable 1507.4.3 minimums:aluminum roll-formed: 0.024 inzinc: 0.027 in; copper: 16 oz per sq ftgalvanized steel: ASTM A653 G-90Fasteners (no manufacturer data):steel roof: galvanized fastenerscopper roof: copper alloy or 300 stainlessAt 2:12 use lapped seams with sealant, or standing seamLapped, nonsoldered panels without lap sealant need 3:12 or steeper.2025 CBC Sec. 1507.4.2, Table 1507.4.3, Sec. 1507.4.4. 2025 CRC R905.10.2 prints the same slopes.CC
The diagram for this lesson, exactly as it appears in the Learning Hub.

The first steps of this lesson

Step 1: Which Code Section Applies

The 2025 California Building Code (CBC) Section 1507.4 covers the installation of metal roof panels, and the 2025 California Residential Code (CRC) Section R905.10 covers the same panels on dwellings and prints the same slope rules. Panels go on a solid or closely fitted deck unless the covering is specifically designed to be applied to spaced supports (CBC Section 1507.4.1). Underlayment follows Section 1507.1.1 (Section 1507.4.5). Structural standing-seam systems are tested to ASTM E1592 or FM 4474, and structural through-fastened systems to ASTM E1592, FM 4474, or UL 580 (CBC Section 1504.4.2).

Step 2: Minimum Slope Depends on the Seam

CBC Section 1507.4.2 sets three minimum slopes. Lapped, nonsoldered seam panels without applied lap sealant need 3 units vertical in 12 horizontal (25 percent). Lapped, nonsoldered seam panels with applied lap sealant need one-half unit vertical in 12 horizontal (4 percent), with the sealant applied per the manufacturer instructions. Standing-seam panel systems need one-quarter unit vertical in 12 horizontal (2 percent). Percent slope is the rise per 12 inches of run divided by 12, so 3 in 12 is 3 / 12 = 25 percent.

The remaining 3 steps, the worked example and the quiz are in the course. This is a preview. The full lesson, with the step-by-step explanations, a worked example and a quick-check quiz, is inside the classroom.

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