Subframe for aluminium composite panels

Subframe for aluminium composite panels

Composite panels are light, but they are large and flexible, so the subframe has to be accurate. Flatness of the rails controls flatness of the finished facade, and the joint pattern comes directly from the rail grid. The subframe can carry cassettes, riveted flat sheets or bonded panels, each with its own rail layout.

Cassette system

Folded composite cassettes hang on horizontal or vertical rails with hooks or slots. Bracket and rail positions are tied to cassette width, with an allowance to adjust each tray in plane and depth. Weight of composite is around 5 to 6 kg/m2 for a 4 mm sheet, which is low enough for most walls.

Riveted or bonded sheets

For flat sheets, rails are placed at the joints and at intermediate points so that each panel is supported at the edges. Rivet holes are drilled oversize in sliding zones. Bonded systems use vertical rails with tape and sealant strips, leaving a clean surface without fixings.

Design points

• Rail spacing depends on panel size, thickness and wind suction at corners and edges, which is higher than in the middle of the wall.
• Aluminium rails and composite panels move together; joints between panels must be sized for the larger of the thermal movements.
• Core type matters for fire: polyethylene core is combustible, while fire-retardant or mineral cores perform better. Facades above 12 m in Georgia are reviewed under Chapter 14 of the Building Safety Rules, and the core is stated in the documents.
• Keep dissimilar metals apart and use stainless rivets.
• Do not use a rail for two cladding layers.

Pricing is on request. Send us your elevations and we will prepare a subframe and cassette calculation.

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