Ventilated attics are designed to reduce humidity in attics and prevent condensation from damaging sensitive building materials of the building envelope. (1) Attics without ventilation are at risk of structural damage as well as reduced thermal resistance. This study measures the moisture conditions in an unventilated attic, and determines if and where condensation forms. It is hypothesized that dew point is reached within the layer of fiberglass insulation over the attic floor. Temperature and relative humidity were measured for seven days in six locations in and around the attic, and were used to determine if dew point was reached within the attic. Results show that dew point was never reached within the layer of insulation, but unexpectedly, it was reached on the surface of the roof sheathing. Two subsequent measurement periods were recorded where all variables are identical to the first study except that the house is unoccupied with the windows closed in the second study, and the house is occupied with the attic windows open in the third study. These studies were preformed in an attempt to identify moisture sources and a ventilation solution.
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