moisturepenetration

Moisture penetration, sometimes written as moisturepenetration, refers to the movement of water in liquid form or as water vapor into or through a material, a building assembly, or an environment. It is a central concern in construction, textiles, wood products, soils, and electronics, where unwanted moisture can cause damage, decay, or performance changes. The term encompasses capillary uptake, infiltration, and vapor diffusion driven by humidity differences.

Mechanisms include liquid transport by capillary rise, gravity-driven seepage, and bulk infiltration; vapor transport by diffusion, advective flow with air movement, and condensation within pores; and hygroscopic uptake where materials absorb moisture at high humidity.

Influencing factors are pore structure and permeability, moisture content and history, temperature, relative humidity, surface condition, air exchange, and driving pressure or vapor pressure gradients. Consequences can include material deterioration, mold growth, corrosion, reduced thermal and acoustic insulation, warping, and changes in mechanical properties.

Measurement and mitigation involve moisture meters and impedance methods, sorption isotherms, diffusion tests, and humidity chamber testing to assess penetration. Mitigation includes proper detailing, vapor retarders, breathable barriers when appropriate, sealing of joints, drainage, and ventilation, as well as selecting materials with suitable moisture compatibility. In electronics, protective coatings and enclosures help prevent penetration; in wood and textiles, appropriate drying, storage, and desiccants limit uptake.