Top-Hat / Aluminium Subframe & Rail Systems

Capral 65 mm aluminium top-hat section in 6063-T5 alloy is the standard workhorse subframe profile for FC sheet, FC panel, solid aluminium, and HPL cladding systems in Australia. Installed horizontally or vertically on helping-hand brackets at 600 mm centres, the top-hat creates a drained and ventilated cavity between the cladding panel and the primary wall. The 65 mm crown accommodates standard FC screw fixings and allows the cladding panel to bridge the cavity without deflection. Anodised or mill finish; cut on site with standard aluminium-rated saw blades.

Z-section aluminium rail in 6063-T6 provides a higher yield strength (160 MPa) than standard T5 extrusions, enabling wider bracket spacing and longer unsupported spans. The Z-profile configuration allows the cladding panel to interlock with the rail using a concealed clip or secret-fix arrangement — eliminating exposed screw heads on the cladding face. Particularly suitable for terracotta slip-fit systems, concealed-fix FC panels, and aluminium cassette cladding where a clean panel face is required. Engineer certification typically required for structural adequacy on buildings Class 2+ over 25 m.

The Ametalin ThermoBLOCK system incorporates an extruded EPDM thermal break within the rail profile, interrupting the conductive aluminium path between the cladding and the primary structure. In NCC 2022 Section J compliance assessments, unbroken aluminium rails create significant thermal bridges that reduce the effective R-value of the wall system by 30–50%. ThermoBLOCK rails maintain the structural performance of 6063-T5 aluminium while satisfying thermal performance requirements for Class 2–9 buildings — critical for NatHERS and NABERS-rated projects.

Ullrich 100 mm heavy-duty top-hat in 6063-T6 alloy provides a wider bearing surface for large-format cladding panels including terracotta laths, sintered stone slabs, and 1,200+ mm FC panels. The 100 mm crown reduces point load concentration at the panel-to-rail contact, extending panel service life and reducing risk of cracking at fixing points. At 2.5 mm wall thickness in T6 alloy, the rail can span up to 900 mm between brackets without exceeding deflection limits — allowing reduced bracket density on concrete or masonry primary structures.