What is the process of water vapor molecules moving through a material driven by moisture gradients called?

The process of water vapor molecules moving through a material driven by moisture gradients is referred to as diffusion. This phenomenon occurs when water vapor concentrations vary between two areas within a material or between the material and the surrounding environment. Water vapor molecules naturally move from regions of higher concentration, where there is more moisture, to regions of lower concentration, where there is less moisture. This movement continues until equilibrium is reached, and it plays a critical role in the drying process during water damage restoration.

Diffusion is a passive process that does not require external energy; it relies on the natural movement of molecules. Understanding diffusion is essential in structural drying, as it helps technicians assess how moisture will migrate through materials, aiding in effective drying strategies.

The other processes listed—convection, conduction, and evaporation—are distinct in their mechanisms. Convection involves the movement of heat and moisture through a fluid (liquid or gas) and is more about the transfer of energy through bulk movement rather than molecular diffusion. Conduction refers to the transfer of heat through direct contact between materials and is not directly related to moisture movement. Evaporation is the process of converting liquid water into vapor but does not specifically describe the transport of vapor through materials. Thus, diffusion most accurately describes the movement