Subframe for HPL panels

Subframe for HPL panels

HPL facade boards are light, flat and workable, but they are organic composites that react to temperature and humidity. A good subframe lets them move without buckling and keeps the plane true. Panels weigh roughly 10 to 18 kg/m2 depending on thickness, a load that aluminium brackets and rails carry comfortably on most walls.

Fixing methods

• Visible fixing: panels are riveted or screwed to vertical rails, using painted heads that match the decor. Rails are placed at every panel joint and at intermediate positions.
• Concealed fixing: undercut anchors on the back of the panel engage horizontal profiles, leaving the face clean.
• Adhesive fixing: panels are bonded to vertical rails with a structural sealant system, for a monolithic surface.

Rail layout

Because HPL boards are rigid, the rail spacing is set by panel thickness and wind load. Vertical rails are most common. Horizontal joints between panels are open or closed with a profile, and vertical joints are aligned with rails. Fixed points are drilled at the right diameter, and sliding points use oversize holes with floating heads.

Design points

• Respect the manufacturer's edge distances for holes.
• Keep the cavity ventilated top and bottom, with insect mesh.
• Use thermal breaks under brackets to reduce cold bridges.
• Account for darker decors, which expand more.
• Because HPL contains organic resin, buildings above 12 m in Georgia are reviewed under Chapter 14 of the Building Safety Rules, and walls with combustible components may need NFPA 285 evidence. The subframe design includes cavity barriers to match.

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

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