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Corners, transitions and compound geometry · Lesson 1 of 4

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.

10 min · 11 slides · 7 questions

All lessons in this module
Slide 1 of 11

What this module covers

Edge metal runs straight until it meets a corner, an open end or a change of condition. This module covers the pieces made for those places: miters, end caps and end terms, tees, step-ups and transitions.

AFS's folder forms straight lengths from FlashDraft legs, angles and blank width. Corner pieces are made differently by each system, so ask AFS how yours will be made.

Corners and ends at a glanceFour panels on a navy field summarising the module: corners are inside or outside and open ends take left or right hand end caps; the project spec governs first, then the system maker, and a number belongs to one job only; each piece is cut at half the corner angle, the saw setting is 90 degrees minus the miter angle, and sloped runs use true length; and check the run: the last piece is 12 in or more, the standard length is 10 ft and the maximum is 10 ft 6 in.Corners and ends at a glanceName the pieceCorners are insideor outside. Openends take a left orright hand cap.Who sets rulesProject spec first,then the maker. Anumber belongs toone job only.GeometryCut at half thecorner angle. Sawis 90 minus miter.Slopes: true length.Check the runLast piece 12 inor more. Pieces:10 ft standard,10 ft 6 in maximum.Example corner legs are not AFS standards.

Four panels summarising the module: name the piece (corners are inside or outside; open ends take a left or right hand end cap); who sets the rules (the project spec first, then the system maker, and a number belongs to one job only); geometry (cut each piece at half the corner angle, the saw setting is 90 degrees minus the miter angle, and sloped runs use true length); and check the run (the last piece is 12 in or more, the standard length is 10 ft and the maximum is 10 ft 6 in).

The module in four panels. The 12 in closer check is the AFS roof edge tool's; the 10 ft standard is the AFS catalog's; 10 ft 6 in is the AFS maximum. Corner legs in the examples are not AFS standards.

Sources

Videos for this lesson

What this video shows: Sheffield Metals' technical department installs inside and outside corner miters where sidewall and headwall flashings meet on a standing seam roof: one manufacturer's method, for reference.

Video: How to Install Inside & Outside Corner Miters for Sidewall & Headwall by The Metal Roofing Channel, on YouTube. Chosen from the video's published description.

Glossary

Miter
A corner piece of the same profile as the run, with two legs, made and delivered as one unit.
Outside corner
A convex corner that wraps outward around the building.
Inside corner
A concave corner that turns inward.
End cap
The closure at an open end of a run, ordered as a left or a right hand.
Transition
An accessory that joins two different conditions in one run, such as a step-up or a peak.
True length
The real length of a sloped line, longer than its length measured on a plan.