Reference Library
Detail reference for expansion joints, flashing, fastener types, and wind load zones — the details that prevent callbacks.
Horizontal Expansion Joint (Floor Line)
ACM / Plate — at every floor line or per 10–12 ft span
A continuous horizontal break in the panel run that allows the facade to move with thermal expansion and slab deflection. The panel above must not be hard-fastened to the panel below — use a two-piece interlocking joint or a slip-joint extrusion with slotted fastener holes.
- Joint width: 3/8"–3/4" typical, sized to movement (≈ 1/4" per 10 ft per 100°F swing)
- Backer rod + sealant, or open reveal with internal flashing
- Internal drip flashing to shed water out of the joint
- Never seal a structural expansion joint solid — it will pump out
Vertical Expansion Joint (Panel Joint)
All panel types — between panel runs / at building joints
A vertical break aligned to a building expansion joint or at the maximum panel-run length. Allows the facade to move horizontally with thermal cycling and building sway.
- Align to structural building joints — never bridge them
- 3/16"–1/2" reveal typical; wider at long runs
- Sliding clip / slotted hole on one side so the panel can move
- Sealant + backer rod, or open joint with internal weather barrier
Corner Joint
ACM / Plate — at outside corners
Corners concentrate movement and water. Use a dedicated corner extrusion or a folded corner panel with an expansion allowance. Avoid butt-joining two flat panels at a corner without a corner detail.
- Prefer a folded corner panel (one piece) over a mitered joint
- If mitered, seal the miter and allow movement at the adjacent joints
- Internal corner flashing behind the joint is mandatory