How to Measure and Order Custom Drip Edge for a Shed Repair

Short answer: Sketch the shed roof, label each edge, and measure the full physical run where trim will sit. Separately record the top leg, fascia leg, drip projection, and any returns or hems from a known-good sample or a supplier-approved drawing. Then turn each run into a piece schedule using the roofing system’s specified cuts and joint laps. A custom profile is worth considering only if the standard replacement part does not match the roof system or the existing edge.

Make a roof map and a profile sketch

Give every edge and profile its own label. A gable-roof shed typically has two eaves and four rake runs—two from the ridge to an eave at each gable end; a single-slope shed has a different edge layout. A roof-to-wall intersection may need a wall-flashing detail rather than ordinary drip edge. The drawing below shows how to keep the run measurements separate from the cross-section legs.

What to gather before measuring

• A tape measure, notebook, pencil, camera, and a helper for long runs if you can measure from a stable, safe location.
• The roof-covering brand and product name, installation manual, existing trim or part label, and shed drawings if available.
• A roof sketch with every eave, rake, corner, roof-to-wall transition, and gutter labeled.
• Photos that show the roof covering, edge, fascia, deck condition, existing flashing, and any joints—taken without removing sound roof materials.
• A safe access plan. Do not measure from a wet, icy, windy, or unstable roof, or lean out from a ladder to reach an edge.

Measure in four passes

1. Identify the roof covering and each edge.

   Record whether the shed has asphalt shingles, exposed-fastener metal panels, or another roof system. Mark each low eave, each sloped rake or gable edge, and any edge that meets a wall. An edge at a wall may need a sidewall flashing assembly, not a drip-edge substitute; the 2024 IRC model text for wall-roof intersections illustrates the separate flashing requirement where that code applies. Roofing terms and trim parts vary by system. For a shingle roof, record the exact product too: GAF's R-141 advisory recommends drip edge at eaves and rakes on its shingle roofs and tells users to follow current shingle-product instructions; that guidance is specific to GAF systems.

2. Inspect what the old metal was covering.

   Photograph the existing profile, its orientation, visible fasteners, joints, and condition of the fascia and roof deck. Soft wood, staining, loose panels, or damaged shingles are repair issues to resolve before covering the area. An old bent or corroded piece can be a misleading pattern; do not treat it as a reliable template without checking the roof manual.

3. Measure the runs along the actual edges.

   Measure from the actual start of one trim run to its end along the edge where the part will sit. A sloped rake is longer than its horizontal projection, so do not substitute the shed footprint. Record the two eaves and two rakes separately even if they look alike. Note corners, breaks, walls, gutters, existing joints, and any change in roof or fascia geometry.

4. Capture the cross-section as a different set of dimensions.

   On a safe, accessible sample or supplier-approved sketch, label each leg in order from the roof side to the outer edge. Record the roof/top leg, fascia-cover leg, drip projection, hems, returns, and bend direction. Also note whether each number is taken inside, outside, or to a bend centerline—the fabricator must tell you which reference it needs. Do not simply add leg measurements and call the sum a flat blank width; bends and hems affect the developed profile.

Turn the edge measurements into a piece plan

A total run is a survey number, not automatically a cut list. For every continuous edge, note the proposed piece start and end, finished cut length, joint location, overlap or connector, and end treatment. Ask the roof-covering manufacturer or supplier which piece lengths and joints are approved for that roof system. Add only documented laps, end details, and cut allowances. There is no universal shed-roof waste percentage.

For asphalt shingles, the 2024 International Residential Code, Section R905.2.8.5 specifies a minimum 2-inch overlap between adjacent drip-edge segments when that model-code provision applies. The section also distinguishes underlayment placement at eaves and rakes. It is a model-code provision for shingle roofs—not a universal joint detail for every shed, jurisdiction, or metal-panel roof. Confirm local adoption and amendments, and follow the specific roof manufacturer's instructions.

Worked example: a small gable shed

Illustrative measurements only: suppose a gable-roof shed has two measured eaves of 10 feet 8 inches each and four measured rake runs of 8 feet 2 inches each—two from the ridge to the eaves at each gable end. Assume the measurements have already been taken along the actual edges and there are no extra returns in this simple sketch.

Now imagine one 10-foot-8-inch shingle-roof eave must be split into a 6-foot piece and a 4-foot-10-inch piece. Under the limited example of a 2-inch approved overlap, those cut lengths cover 10 feet 8 inches: 6 feet + 4 feet 10 inches − 2 inches. That arithmetic only illustrates how a specified lap changes coverage. It does not tell you where a joint belongs, include end cuts, or replace the roof-maker's instructions. If its detail calls for a different lap, use that requirement instead. Do not apply this shingle example to metal panels.

Prepare a complete order brief

• Roof: covering brand/model, roof edge location, and relevant installation-manual detail.
• Runs: edge ID, start/end, measured length, units, and whether the edge is an eave, rake, or another condition.
• Profile: labeled cross-section, leg dimensions, bend direction, measurement reference, material/thickness requirement, color or finish, and any approved hem or return.
• Pieces: each cut length, joint location, required overlap or connector, end treatment, and the source of that requirement.
• Evidence: roof sketch, photos, an undamaged sample if one is available without dismantling the roof, and the supplier's written confirmation of the part.

If the roof uses a proprietary panel system, ask its supplier to identify the matching edge trim before commissioning a custom shape. Fabral's Grandrib 3 and Alu-Tuff guide, for example, uses product-specific roof sketches, sections, accessory names, and order forms. Its dimensions and parts apply to the named system, not to every shed roof.

Where Trimgy may help—and what it does not do

If a roofer or roofing supplier confirms that a custom sheet-metal cross-section is appropriate, Trimgy can help you draw that profile and view an instant trim-price estimate. The drawing interface uses inches and a quarter-inch grid increment. The live material selector includes 22-, 24-, and 26-gauge steel and 0.032-, 0.040-, 0.050-, and 0.063-inch aluminum thickness options; which option suits a roof is a separate decision for the system supplier or fabricator. The pricing endpoint rejects profiles with a calculated stretch-out over 48 inches.

The profile drawing is not a roof survey or a confirmed cut list. Trimgy does not choose eave versus rake trim, determine the correct joint or lap, calculate a universal waste amount, or certify a profile for local code, roof compatibility, fabrication, or leak prevention. Its estimate returns trim pricing based on the drawn profile, selected thickness and color, and entered footage; it expressly excludes shipping and tax.

To order in the current interface, you must sign in, save the trim, select a thickness and color, choose start and end edge types, and resolve unsaved changes or intersecting lines. The Order panel also requires linear footage in multiples of 10. That is an application input rule—not a roofing cut plan or a waste recommendation. Shipping quotes and applicable tax are handled separately in the order flow; review the available charges and full total before payment. The drawing workspace opens behind a sign-in screen.

Mistakes that lead to a mismatched order

• Measuring the footprint instead of the roof edge. Measure a rake along its slope, not its horizontal projection.
• Combining eaves and rakes too early. Record each run and profile separately until the manufacturer confirms they use the same part.
• Using one dimension for both run and profile. Feet along the edge determine the run; inches around the cross-section describe the shape.
• Copying an old piece without checking it. A bent or corroded sample may not show the original profile or correct orientation.
• Forgetting the seam. Joint laps reduce how much edge a set of cut pieces covers. Use the specified lap, not a guessed allowance.
• Assuming custom trim solves a roof problem. It does not repair deteriorated sheathing, a failed roof covering, or missing system flashing.
• Reading the estimate as a delivered total. Trimgy's instant trim estimate excludes shipping and tax; check the separate order flow.

Safety and code notes

Measuring does not require walking on the roof. If an edge cannot be reached safely from the ground or a stable platform, stop and hire a qualified roofer. Keep ladders on stable ground, do not lean beyond the rails, and avoid work in wet, icy, or windy conditions. Sheet-metal edges are sharp; use suitable gloves and eye protection when handling a sample. OSHA's ladder guidance is written for construction workers and is not a homeowner-specific risk assessment. A metal-roof manufacturer's own safety warnings also apply to its panels.

Code applicability depends on the roof covering, shed, jurisdiction, and adopted code edition. The 2024 IRC citation above concerns asphalt-shingle roofs; a small shed may have different local permit or code scope, and metal-roof assemblies use their own product instructions. Ask the local building department when requirements are unclear.

Related guide

This article focuses on measurements and order preparation. For a separate overview of named drip-edge profile types and their typical geometry, see Custom Drip Edge Types and When to Use Each. Confirm any profile or dimension against current product instructions and local requirements before ordering.