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Moisture control in a ventilated attic

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Abstract
Temperature and relative humidity in the roof space above a well insulated ceiling depend mainly on the outdoor climate. During the winter, the roof space is cold and humid, while during the summer, it is warm and dry. However, if the ceiling between the interior of the house and the roof space is permeable to air, warm and moist air can find its way into the roof space and raise the relative humidity. this may result in the growth of mildew and, in severe cases, rot. One way to decrease the risk of damages during winter conditions is to choose moisture-resistant materials. Another way is to modify the construction and employ additional thermal insulation beneath the roof tiles. This will result in the temperature in the roof space being higher, thus decreasing the relative humidity. Measurements made in a test roof space, employing five different forms of construction, bear this out. Insulation beneath the roofing tile improves the roof space climate.
Date
12/1992
Author(s)
I Samuelso
Page(s)
512-516
Keyword(s)
moisture control; ventilated attic; thermal performance; insulation;


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