Short answer: Before you order custom sheet-metal trim, field-check the actual installation locations; draw the profile from a clearly marked viewing side; label every leg, bend direction, and unit; and list each run, piece count, and piece length separately. Record the specified material, thickness, and finish, then compare the notes against a dimensioned sketch and labeled photos. Ask the fabricator which measurement reference and joint allowance its product uses.
These are different measurements. The cross-section describes the shape of one trim piece. The takeoff describes how many pieces you need, where they go, and their lengths. A correct drawing cannot fix a short takeoff, and a correct total footage cannot tell a shop which way to bend the metal.
Do not order from a nickname or a photo alone. Terms such as “four-inch cap” can refer to one face, the top, or a total flat width. A photograph gives context, but its perspective does not establish dimensions. Use a labeled section sketch and a separate piece schedule.
1. Set up your field notes before measuring
Start with the product that the trim must meet: roof panel, siding, window or door, wall, fascia, or another surface. Find the current installation manual, detail drawing, or project specification for that system. Note the manufacturer, product name, and revision if shown. The attachment, overlap, and measurement references for one system are not a universal detail for another.
Gather a tape measure, straightedge, pencil, notebook or grid paper, camera, and the relevant product instructions. An angle finder may help record an existing corner or slope; record what you measured rather than converting it into a guessed profile. For each photo, add a location label—such as “Gable left / run R1”—that matches your notes.
Metal Sales' wall-system installation guide says dimensions should be verified by field measurements before ordering and installing materials; the guide also describes system installation as a dangerous procedure that should be supervised by a knowledgeable, trained erector. Its 2024 product guide asks for custom trim drawings with shape, quantity, gauge, dimensions, color, and angle information. These are examples of one manufacturer's instructions, not a universal order form; they show why a single “total feet” number is not a complete trim specification.
2. Label the profile orientation and every leg
Draw the trim as a cross-section viewed from the end of the piece. Choose a consistent view, then mark which side faces outside, the roof, the room, or the building as appropriate. Add a start point, an end point, and an arrow showing the order in which you trace the profile. Label each straight leg A, B, C, and so on, and write down each leg's direction and length.
Do not rely only on “left,” “right,” “up,” or “down”; those words change when the sketch is flipped. For a sloped roof or an angled return, mark the angle or the existing reference surface and ask the manufacturer which angle convention it uses. If the supplier's drawing shows inside, outside, or centerline dimensions, state which convention your numbers use rather than assuming they are interchangeable.
3. Keep cross-section dimensions separate from run lengths
Draw one row in your takeoff for each trim profile and location. A wall-to-roof flashing, a rake edge, and a fascia cap may all be metal, but they do not become one profile just because they are on the same shed. Measure each run where the part will sit. If it follows a slope, write that your figure is the length along the installed edge, or state the alternate reference required by the product instructions.
List the number of pieces and the length of each piece, not only their sum. Keep corners, end caps, transitions, and special short pieces separate from straight-run footage until the supplier tells you how they are priced and joined. Do not add an arbitrary waste or lap percentage: ask for the selected system's cut, joint, and length allowances.
| Location / profile ID | Cross-section reference | Material / thickness / finish | Piece count and each length | Photo / sketch ID |
|---|---|---|---|---|
| R1 |
View side: Legs A–__: |
Material: Thickness: |
Count: Lengths: |
Photo: Sketch: |
| R2 |
View side: Legs A–__: |
Material: Thickness: |
Count: Lengths: |
Photo: Sketch: |
| Corner / end |
Part / angle: Reference: |
Confirm with supplier: | Count: Piece length: |
Photo: Sketch: |
4. Check these common measurement mistakes
| Mistake | Check before you request a quote |
|---|---|
| Flipped or mirrored profile | Mark which face is outside/building-side, start and end points, and the order of bends. Compare the sketch to a photo taken from the same side. |
| One label instead of every leg | Give each straight segment its own letter and dimension. Ask whether the supplier wants inside, outside, or another reference at the bends. |
| Mixed inches and feet | Write the unit beside every dimension. Use inches for the profile sketch and label the run schedule in feet or the unit requested by the supplier. |
| Run length confused with profile width | Keep the cross-section sketch and the location-specific length schedule in separate boxes. A profile's flat width is not the installed run footage. |
| Only a total footage | List the quantity and individual lengths for each profile and location; keep corners and other pieces separate until the shop confirms their treatment. |
| “Steel” or “heavy gauge” without a spec | Record the specified metal, thickness/gauge, and finish for each profile. Confirm compatibility and availability with the panel/trim manufacturer or fabricator. |
| Photo used as a measuring tool | Use a photo to identify the location and obstacles; use written dimensions and a section sketch for the shape. Label both with the same profile ID. |
| No final drawing comparison | Before approving a shop drawing, compare its orientation, every leg, units, material, thickness, piece schedule, and marked location against your notes. |
5. Review the manufacturer's detail and order information
Give the supplier your sketch and piece schedule, then ask it to confirm the measurement surfaces, profile orientation, angle notation, material, thickness, finish, joint or cut allowance, and whether special accessories are needed. Metal Sales' 2024 guide is one example: its request for a custom trim drawing asks for the shape, quantity, gauge, dimensions, color, and degrees of angles. It is a product supplier's request—not a standard for every shop—so use the current instructions from the company making your part.
If a trim piece is also flashing at a roof, exterior wall, or opening, treat that as part of the assembly's water-management detail, not just a bent shape. The 2024 International Residential Code (IRC) model text in R703.4 addresses approved corrosion-resistant flashing and water entry; R703.4.1 points to the window/door manufacturer's flashing instructions, or the flashing manufacturer's instructions when the opening instructions do not address the application. Local adoption and amendments vary. A measurement checklist does not determine code compliance or prove that a detail will keep water out.
Where Trimgy helps—and what it does not do
After the profile and measurement reference have been confirmed, Trimgy can help you draw one cross-section and view its segment lengths. The drawing canvas uses inches and snaps to quarter-inch steps. Each segment is labeled in inches; its displayed length is rounded to the nearest quarter inch and formatted with two decimal places. A user can open a segment-length editor from the canvas, and the entered length is rounded to the same quarter-inch increment. The current canvas is 30 by 15 inches.
Trimgy's current thickness selector lists 22-, 24-, and 26-gauge steel and 0.032-, 0.040-, 0.050-, and 0.063-inch aluminum. Color availability varies by thickness. Those are interface choices, not a recommendation or confirmation of coating, exposure suitability, compatibility with a roof or siding system, or material availability from a specific fabricator. Use the project specification and supplier instructions to choose.
The pricing calculation uses the drawn points, selected thickness and color, and footage. Its underlying endpoint accepts either total linear footage or a quantity multiplied by one piece length; the price response is in USD and includes per-linear-foot and total fields. The current drawing price panel shows a per-linear-foot estimate. The order panel asks for total linear footage in multiples of 10 feet, so it is not a multi-row cut list for pieces of different lengths. Keep your separate piece schedule and confirm it with the shop. The pricing calculation rejects profiles with a stretch-out over 48 inches.
To place an order, the current order flow also requires a saved profile, selected thickness and color, start/end edge types, no unsaved changes or intersecting lines, a profile within the stretch-out limit, and valid order footage. The estimate explicitly excludes shipping and tax. Shipping quotes are requested separately using destination information, linear footage, and profile stretch-out; tax is calculated separately using project postal-code information and shipping cost. Check the complete charges in the order flow before payment.
Trimgy does not measure the building, decide which side of a trim profile faces out, select a flashing or fastener detail, calculate a complete project takeoff, or certify dimensions, installation, code compliance, or leak prevention. Sign-in is required to start drawing. Use it to sketch and price a profile after you have checked the real-world measurements—not as a substitute for the field notes or manufacturer review.
Next step: Compare your takeoff and profile with the supplier's current instructions or shop drawing. For a broader contractor-oriented ordering overview, see How to Order Custom Sheet Metal Trim; confirm current app behavior and charges in the live order flow. Then open Trimgy to draw one confirmed profile at a time.
Sources and scope
- Metal Sales, 2024 Product Guide. Its custom-trim request describes supplying a drawing with shape, quantity, gauge, dimensions, color, and angle information. This is that manufacturer's guidance, not a universal order standard.
- Metal Sales, Installation Guide for metal wall systems. It calls for field verification of dimensions before ordering and installation and warns that the system work is dangerous and should be supervised by a knowledgeable, trained erector. This is manufacturer-specific guidance, not a universal installation rule.
- International Code Council, 2024 IRC R703.4 — Flashing. Model-code provisions for approved corrosion-resistant flashing at specified building locations; check the locally adopted edition and amendments.
- International Code Council, 2024 IRC R703.4.1 — Flashing installation at exterior window and door openings. Model-code reference to the fenestration manufacturer's instructions, or flashing manufacturer's instructions where the opening instructions do not address the application.
- OSHA, Portable Ladder Safety QuickCard. Workplace safety guidance that includes ladder inspection, stable setup, and maintaining contact while climbing; homeowners should follow safe-work practices and ladder-maker instructions.
Frequently Asked Questions
What should I measure before ordering custom metal trim?
Record the cross-section separately from the installed run: label every leg, bend direction, viewing side, and unit; measure each location-specific run along the path where the trim goes; and list the number and length of each piece. Add the specified material and thickness, then compare the notes with a labeled sketch and photos. Ask the manufacturer or fabricator to confirm measurement references and cut/joint allowances.
Does Trimgy display dimensions in inches?
Yes. The drawing canvas labels each profile segment in inches. The canvas snaps to quarter-inch increments, and the displayed segment lengths are rounded to the nearest quarter inch while formatted with two decimal places. Trimgy geometry is a drawing and pricing aid, not a manufacturer's shop drawing or a confirmation of the installed measurement.
Can the Trimgy order form take a piece-by-piece cut list?
The current order panel asks for total linear footage in multiples of 10 feet; it is not a multi-row cut-list form. The underlying pricing endpoint accepts total linear footage or a quantity multiplied by one piece length. Keep your actual count and each cut length in a separate schedule, and confirm how the supplier wants them grouped.
Which material and thickness should I choose?
Use the project's specification and the selected trim or panel manufacturer's instructions; Trimgy does not assess exposure, substrate compatibility, or code suitability. Its current selector lists 22-, 24-, and 26-gauge steel and 0.032-, 0.040-, 0.050-, and 0.063-inch aluminum. Color availability depends on the selected thickness.
Does the Trimgy price estimate include shipping and tax?
No. The trim-price estimate explicitly excludes shipping and tax. In the separate order flow, shipping quotes use destination information, linear footage, and profile stretch-out; tax is calculated separately using project postal-code information and shipping cost. Review the charges and full total shown before payment.
Can I use a photo instead of a dimensioned profile sketch?
Use both when possible. A photo shows where the trim goes, but perspective and scale make it a poor substitute for labeled dimensions. Add a cross-section sketch with a viewing direction, start and end, every leg, units, and bend directions, then label photos so they match the sketch.
When should I ask a professional to measure or review the trim?
Ask a qualified installer, roofer, siding or window professional, or metal fabricator when the trim is part of a roof, wall, or opening's water-management system, when the manufacturer's reference surfaces are unclear, or when safe access requires roof or ladder work. Follow the locally adopted code and the instructions for the specific products.