The ASTM C1242 undercut anchoring system represents the pinnacle of mechanical stone attachment. Unlike traditional kerf fixing, which relies on cutting slots into the stone edges (creating stress concentrations), undercut anchoring involves precision-drilled holes in the back of the panel. This allows for:

• Stress Distribution: The load is distributed deeper into the stone, significantly reducing the risk of edge spalling.
• Higher Load Capacity: Back-bolts provide superior pull-out resistance, critical for high-rise facades facing extreme wind pressures.
• Seismic Resilience: The mechanical bond offers controlled flexibility, allowing the facade to dissipate energy during seismic events without panel detachment.