A state-of-the-art research assessment for residential attic condensation

A brief synopsis of recent analytic and experimental studies is given. Conclusions are that convective transfer of water vapour into an attic from the living space below often transports more moisture than diffusive transfer through the ceiling construction. Large quantities of moisture are stored in the roof sheathing during warm spring and summer periods. Solar loading during mild winter periods can produce desorption of moisture from the sheathing. This paper reviews the formulation of mathematical relationships among physical parameters governing moisture transfer within attics. In order to model completely all moisture transfer processes, further experimental measurements are needed to quantify attic ventilation rates and convective air flows into the attic from the house below.