Lap siding refers to horizontal siding boards installed with each board overlapping the one below it, a traditional and highly effective installation method for shedding water down and away from the wall surface rather than allowing it to pool or work its way behind the siding.
This overlapping technique is used across many different siding materials, including wood, fiber cement, and vinyl, making lap siding more of an installation style than a specific material category.
Because the overlap creates a natural water-shedding path, lap siding remains one of the most common and reliable siding installation methods across virtually all climate regions and architectural styles.
What Does Lap Siding Involve?
- Horizontal boards or panels installed with overlapping edges
- Consistent reveal, or exposed width, along the wall
- Proper nailing above the overlap to allow water shedding
- Coordination with trim at windows, doors, and corners
Why Is Lap Siding Important?
The overlapping installation method inherently sheds water downward and outward from the wall, a simple but genuinely effective water management principle that has made lap siding the dominant installation style across most siding materials and regions for generations. This proven approach continues to outperform alternative styles for straightforward, reliable weather protection.
Proper nailing placement matters significantly to lap siding’s performance, since fasteners driven too low, through the overlap area rather than above it, can restrict the material’s ability to move naturally and may compromise the water-shedding function the overlap is specifically designed to provide. This attention to fastening detail is a hallmark of quality installation regardless of the specific material used. This care during installation is a hallmark of quality work regardless of material chosen.
Lap Siding vs. Board-and-Batten Siding
Lap siding uses horizontal, overlapping boards for water shedding. Board-and-batten siding uses vertical boards with narrower strips, called battens, covering the joints between them, an entirely different installation approach and visual style.