Survey of moisture levels in attics.

A survey of twenty residential buildings was conducted to observe the impact of ventilation strategies on moisture· accumulation in attics. The objectives of the survey were to record attic lumber moisture content levels over a period of one year and to assess the ventilation characteristics of the attics in order to account for the recorded moisture levels. The sample homes represented a range of ages, construction types and attic venting formats. Five of the houses were located in a coastal climate. Two test protocols, developed specifically for this project. were applied to the sample. The test protocols determined attic airtightness and attic air change rates. Moisture monitoring equipment was installed in each attic, and periodic measurements were taken for one year.  This report presents the findings of the survey and offers an assessment of  the two test procedures used.