Roofing (C-39) · Lesson 6 of 6

Shingle Roof Flashing: Drip Edge, Step Flashing, Valleys, and Crickets

"Shingle Roof Flashing: Drip Edge, Step Flashing, Valleys, and Crickets" is lesson 6 of 6 in the Roofing (C-39) Learning Hub. It opens with "Where Flashing Is Required and What It Is Made Of" and works through 5 short steps, then a worked example you can check yourself against.

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Steps in this lesson

  1. Where Flashing Is Required and What It Is Made Of
  2. Drip Edge at Eaves and Rakes
  3. Sidewall Step Flashing
  4. Valley Linings
  5. Crickets and Saddles Behind Wide Penetrations

The worked example in the course applies this lesson to a realistic job in 6 steps, from "Eave drip edge" through "Cricket check".

What you'll be able to do

  • Explain the main idea of "Shingle Roof Flashing: Drip Edge, Step Flashing, Valleys, and Crickets" in plain language you can use on the exam.
  • Apply this step with confidence: "Sidewall Step Flashing".
  • Apply this step with confidence: "Valley Linings".
  • Apply this step with confidence: "Crickets and Saddles Behind Wide Penetrations".
  • Test yourself on the worked example and the quick-check quiz inside the classroom.
Shingle Roof Flashing: Drip Edge, Step Flashing, CricketGABLE ROOF PLAN, 6:12EAVE 44 ftRIDGERAKE 19.0 ftRAKE 19.0 ftCHIMNEY 48 inCRICKETSIDEWALL 12 ft29 step flashingsEAVE 44 ftUnderlayment over drip edge at eaves, under it at rakes.COUNT THE PIECESDRIP EDGEEaves: 2 x 44 = 88 ftRake: 17 ft run x 1.118 = 19.0 ftRakes: 4 x 19.0 = 76.0 ftTotal: 88 + 76.0 = 164.0 ft10 ft piece, 2 in lap = 9.83 ft each164.0 / 9.83 = 16.7, so 17 piecesFasteners 12 in o.c.: at least 164STEP FLASHING12 ft = 144 in; 144 / 5 in exposure = 28.8One piece per course: 29 pieces48 in chimney is over 30 in: cricket164 ft drip edge = 17 pieces; 12 ft sidewall = 29 step flashingsChimney 48 in wide (over 30 in): cricket on the ridge sideCRC R903.2.1, R903.2.2, R905.2.8.1 to R905.2.8.5; CBC 1503.2, 1503.5, 1507.2.8.1 to 1507.2.8.3.Drip edge: 2 in laps, fasteners 12 in o.c. Step flashing at least 4 in x 4 in. 10 ft pieces, 5 in exposure assumed.CC
The diagram for this lesson, exactly as it appears in the Learning Hub.

The first steps of this lesson

Step 1: Where Flashing Is Required and What It Is Made Of

Flashing must be installed at wall and roof intersections, wherever there is a change in roof slope or direction, and around roof openings; the CBC also lists gutters (2025 California Residential Code R903.2.1; 2025 California Building Code 1503.2.1). Where the eave of a sloped roof meets a vertical sidewall, flashing must divert the water away (R903.2.1). Metal flashing must be corrosion resistant and not less than 0.019 inch thick (No. 26 galvanized sheet). For asphalt shingles, base flashing may also be mineral-surfaced roll roofing weighing at least 77 pounds per 100 square feet (R905.2.8.1; CBC 1507.2.8.1), and cap flashing is corrosion-resistant metal of at least 0.019 inch.

Step 2: Drip Edge at Eaves and Rakes

A drip edge is required at the eaves and rake edges of shingle roofs. Pieces lap at least 2 inches, extend at least 1/4 inch below the sheathing and back onto the roof deck at least 2 inches, and are fastened at not more than 12 inches on center (CRC R905.2.8.5; CBC 1507.2.8.3, which also requires a vertical leg at least 1 1/2 inches wide). The order matters: underlayment goes OVER the drip edge at the eaves and UNDER the drip edge at the rakes, so water runs onto the metal at the eave and cannot get behind it at the rake.

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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