Meaning
Variation in vapor density found across the thickness of a material or between two environments drives moisture migration. Facility managers track a relative humidity gradient to understand the movement of moisture through walls or floors. High saturation zones drive vapor toward drier areas until the system stabilizes.
Equilibrium Drive
Vapor moves toward drier zones until the internal pressure of the material matches the surrounding air. This relative humidity gradient acts as the engine for moisture movement in porous solids. Controlling the temperature of the air on both sides of a barrier helps manage the steepness of this change.
Installation Window
Sensitivity to moisture makes many adhesives prone to failure if the base material is too wet. If the relative humidity gradient shows high moisture deep in the slab, the surface will likely fail after the floor is sealed. Measuring the profile at different depths provides a more accurate picture than a simple surface test, allowing for a safer decision on when to begin the work.
Vapor Control
Membranes are installed to block the flow of air and moisture. They effectively break the relative humidity gradient by providing a high resistance layer. Without these barriers, the migration of vapor can lead to mold growth or structural decay.
