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Corners, transitions and compound geometry · Lesson 4 of 4

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.

9 min · 11 slides · 6 questions

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Slide 1 of 11

Four faults to catch

Most corner faults are set up before anyone climbs the roof: in the takeoff, the cut list and the order. The drawing pairs a right and a wrong way for four of them, and names whose rule each is.

Four corner faults, right and wrongFour rows, correct on the left and wrong on the right. One: the cleat joined through the corner as the system's guide shows, versus a cleat broken at the corner. Two: pieces split evenly beside the miter, versus a sliver beside it. Three: a miter end joint with a splice plate and sealant, versus a bare butt joint. Four: a sloped run ordered at its 17.889 ft true length, versus at its 16 ft plan length, which falls short.CorrectWrongcontinuousbrokensplit evenlysliver at miterplate + sealantbare butt joint17.889 ft true16 ft plan: short1234

Four pairs, correct on the left and wrong on the right: a cleat joined through the corner versus a cleat broken at the corner; a full piece beside the miter versus a sliver beside it; a miter end with splice plate and sealant versus a bare butt joint; a sloped run ordered at its true length of 17.889 ft versus at its 16 ft plan length, 22-11/16 in short.

1
Cleat at the corner: joined as the system's guide shows (a continuous cleat line on Drexel drip edge, fascia and gravel stop), not broken off
2
Last piece: 12 in or more, never a sliver beside the miter
3
Miter end: splice plate and sealant bead, not a bare butt joint
4
Sloped run: ordered at 17.889 ft true length, not 16 ft plan length
Whose rule each is: 1 Drexel drip edge, fascia and gravel stop guides (copings follow their own guide); 2 the AFS roof edge tool and Drexel; 3 Drexel Snap Coping-Max; 4 the AFS roof edge tool. Rows 1 to 3 are plan views; row 4 shows the slope from the side. Not to scale.

Sources

Glossary

Closer piece
The last, shorter piece of a run; the AFS roof edge tool flags one under 12 in.
Cleat line
The line of continuous cleat the edge metal or coping hooks onto. Drexel's drip edge, fascia and gravel stop guides keep it continuous at miters; segmented-cleat copings such as Snap Coping-Max have none.
Hand
Whether an end cap or end term fits the left or the right end of a run.
End restraint
Fasteners that stop an end cap or end term moving along the run.