Inspectors use the tool to create a "floor elevation map" of a home. By setting a "zero point" (benchmark), they can move through different rooms to detect if a foundation has settled or shifted.
The term is also associated with roof and wall sheathing from Huber Engineered Woods . aka levels zip work
A ZIPLEVEL is a high-precision, pressurized altimeter used to measure vertical distances and elevation differences. While it is often referred to as a "zip level," it is technically a hydrostatic tool that uses a pressurized liquid-filled cord connected to a base unit to provide digital readings. Inspectors use the tool to create a "floor
Understanding ZIP Levels in Construction and Professional Work aka levels zip work