Water and water vapor transport in two-layer systems where one layer acts as water retarder are analyzed. In the experimental work, four external paints supposed to protect the underlying structure against water under common service conditions are applied on glass fiber reinforced concrete substrates. The water absorption coefficient and the effective water vapor diffusion coefficient are chosen as evaluation parameters for the assessment of water and water vapor transport properties of the systems. In the water absorption experiments, two consecutive quasi-steady regimes are identified, the first with an almost constant water flux into the system, and the second obeying the square-root-of-time rule for cumulative mass of water in the system. The water protective qualities of all studied paints can be considered as satisfactory for common service conditions. The effective diffusion coefficients of all systems are found to be within the error range of the measuring method compared to the substrate itself, which is a very positive feature for external paints.

• material properties: hygrothermal
• measurement: vapor diffusion properties, WVT

1. A comparison of different techniques to quantify moisture content profiles in porous building materials
2. A comparison of various techniques for determination of moisture diffusivity from moisture profiles
3. A transient method for measuring the water vapor diffusion in porous building materials
4. Determination of temperature- and moisture-dependent thermal conductivity by solving the inverse problem of heat conduction
5. Determination of the liquid water diffusivity from transient moisture transfer experiments  

1. A comparison of various techniques for determination of moisture diffusivity from moisture profiles