Corners, transitions and compound geometry
The corner, end and transition pieces of an edge metal run, who sets the corner rules on a job, how to find miter angles and true lengths and split a run between corners, and how to diagnose corner faults from the takeoff to the roof.
4 lessons · about 38 min · 14 diagrams · 1 video
Version 1.1.0
Builds on these modules
Lessons
0 of 4 complete
Lesson 1 · 10 min · 11 slides · 7 questions
Corners, transitions and compound geometry: principles and terminology
Where a straight run of edge metal stops being straight: miters, end caps, tees, step-ups and transitions, why corners matter, and the hand hazards of cut edges.
You will be able to: Name the corner, end and transition pieces of an edge metal run, tell inside from outside corners and plan length from true length, and state the safety boundaries.
Not startedStart →Lesson 2 · 9 min · 9 slides · 6 questions
Corners, transitions and compound geometry: materials, standards and design constraints
Project specs and system makers set different corner rules: leg lengths, joint-free zones, sealed, welded and soldered corners, gaps, cleats and approval drawings, inside AFS limits.
You will be able to: Find who sets a corner's leg length, joints, gaps and joining method on a job, and keep every number labelled as that spec's or that maker's.
Not startedStart →Lesson 3 · 10 min · 10 slides · 7 questions
Corners, transitions and compound geometry: methods and worked application
Bisecting a corner, the half-angle rule and the saw-setting trap, three pattern development methods, then worked examples: a sloped run, a run between corners, and why corners go in first.
You will be able to: Find a miter angle and saw setting, choose a pattern development method, convert a sloped run to true length and split a run between corners into pieces, recording inputs and units.
Not startedStart →Lesson 4 · 9 min · 11 slides · 6 questions
Corners, transitions and compound geometry: defects, verification and case study
Wrong corner types and hands, slivers beside a miter, broken cleat lines, bare miter ends, loose end caps, wrong gaps and short sloped runs; then an L-shaped parapet worked through and checked.
You will be able to: Diagnose the common corner faults from the takeoff to the roof, choose the documented correction, and record the evidence a reviewer needs.
Not startedStart →
Practical task
Take off and document one coping or fascia edge with at least one corner, one sloped run and one open end (a real job or the case study), as a job packet a reviewer can check against its sources.
Hand in
- A decision rationale: which project spec and which system govern the corners, with the leg length, joint rules, gap and joining method each one sets, and what to ask AFS about how the corner pieces will be made
- A marked-up plan or sketch: every corner marked inside or outside, every open end with its end cap hand, every transition named
- A measurement sheet: each run as measured, plan-projected runs converted to true length with the slope and the formula, net lengths after corner legs, pieces, the last piece and joints, with units
- For any corner that is not 90 deg or that joins runs of different slope: the miter angle, the saw setting and the edge each is measured from where they apply, and a note that it needs an approval drawing and is not ordered as a stock miter
- A quality checklist completed for the edge, and a defect analysis of one fault found or set up: what it was, whose rule it breaks and the correction
Rubric
| Criterion | Meets the standard when |
|---|---|
| Sources | Every number names its source: the project spec, the system guide, the AFS tool or limits, or the plan. |
| Corners and ends | Every corner type and end cap hand matches the plan, and the corner count is plausible for the outline. |
| True length | Every sloped run is converted to true length with the slope stated and the arithmetic shown. |
| Pieces | Net lengths, piece counts and last pieces are correct, no straight piece exceeds AFS limits and no closer under 12 in sits beside a corner. |
| Geometry | Any non-90 corner shows the half-angle, the saw setting and the reference edge; every non-90 or sloped corner (including one joining a level run to a sloped run) is flagged for an approval drawing, never ordered as a stock miter. |
| Defect analysis | The fault, the rule it breaks and the documented correction agree with the named source. |
| Safety | The packet notes the hand protection used for cut edges and the OSHA rule that applies in the shop or on the jobsite. |