The nailing holes in aluminum and vinyl siding are elongated to allow for what?

The nailing holes in aluminum and vinyl siding are elongated to allow for expansion and contraction. Both aluminum and vinyl are materials that can expand in high temperatures and contract in lower temperatures. This movement occurs due to changes in the weather and temperature conditions. The elongated holes provide the necessary flexibility by allowing the nails to move slightly, which accommodates the natural shifts in the siding material without causing damage, warping, or buckling. This design feature ensures a properly installed siding system that can withstand various environmental changes while maintaining its integrity and appearance over time.