Expressed Joint / Vertical Joint Flashing

Extruded aluminium H-section expressed joint flashings create a distinct architectural shadow line at panel-to-panel joints in FC sheet and FC architectural panel cladding systems. The H-section grips both panel edges and forms the visible expressed joint — typically 10–20 mm wide — that is a deliberate design feature in contemporary facade architecture. Available in anodised silver or custom powder-coat colour. The H-section includes a small back channel that provides a path for any water penetrating the joint to drain — not a fully sealed joint. A backer rod and sealant is applied in the back channel in moisture-critical applications.

Z-section aluminium flashings at vertical panel joints are installed behind the cladding panel edge, spanning the gap between adjacent panels and deflecting wind-driven rain back to the outer face. The Z-flashing is not visible from the exterior — it is a concealed backup to prevent water passing through the open joint between panels. The front leg of the Z-flashing faces out and laps over the inner edge of the panel behind it; the back leg is fixed to the subframe. Used in open-joint and large-gap panel systems where a sealant joint at the vertical edge is not practical or desired.

Stainless 316 expressed joint flashings at structural movement joints must accommodate both expected movement and maintain weatherproofing throughout. Movement joints in concrete-framed buildings typically occur at expansion joints, construction joints, and at the junction between different structural elements (e.g., tower-to-podium). The flashing profile must provide a minimum 25 mm free movement each side of the joint centreline, with a flexible backing — typically a closed-cell polyethylene foam backer — to prevent the flashing profile from collapsing into the joint. Structural engineer must define the expected movement before the flashing is designed.

Open-joint rainscreen systems (terracotta, large-format FC panels, sintered stone) rely on a concealed Z-flashing behind all vertical and horizontal panel joints — no sealant is used at the panel edges. The Z-flashing intercepts wind-driven rain that enters the open joint and directs it back to the face through the cavity below. The open joint allows the cavity to be fully ventilated — a key advantage over sealed systems. The Z-flashing must be continuous and without gaps; it is typically a lightweight anodised aluminium extrusion fixed to the horizontal rail or a dedicated vertical rail behind the panel joints.