TL;DR
Lap siding exposure is the height of each board face left visible to the weather after the course above overlaps it, set by snapping layout lines so rows land evenly at windows, eaves, and corners. Manufacturers cap it, a 8.25-inch fiber cement plank is commonly limited to 7 inches, because the overlap provides the weather seal and the nailing zone.
What it means
Lap siding exposure is the height of each board face left visible to the weather after the course above overlaps it, set by snapping layout lines so rows land evenly at windows, eaves, and corners. Manufacturers cap it, a 8.25-inch fiber cement plank is commonly limited to 7 inches, because the overlap provides the weather seal and the nailing zone. Stretching it to save material thins that overlap and voids warranties, while tightening it slightly lets installers balance courses on a wall, a layout skill visible from the curb.
Where it sits in the glossary
Lap siding exposure is part of the Trade jargon group inside the ProFix Directory glossary. Browse every term in this category from the glossary index.
Why Ohio homeowners should know it
This is a term Ohio homeowners encounter when reading contractor quotes, hiring paperwork, or inspection reports. Understanding it well enough to ask one good follow-up question is usually all the protection a homeowner needs.
ProFix Directory keeps definitions short on the index page and saves the longer context — Ohio-specific rules, where the term comes from, and which ProFix tools touch it — for these per-term pages so the term is easy to cite and easy to share.
ProFix tools that touch this term
See also
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