Create Locking Tabs

What happens here

The worker then uses a specialized siding punch tool (often referred to as a "snap lock" punch or "utility trim" punch). He aligns the tool along the main horizontal cut line on the siding panel and repeatedly squeezes the handles. This action creates a series of small, upward-facing tabs or "lugs" on the back side of the siding. These tabs are essential for the next step, as they will securely interlock with the receiving groove of the J-channel or utility trim installed along the window sill, holding the siding in place.

Goal: Prepare siding for secure, fastener-free attachment