Mothballing vacant buildings in the Pacific Northwest: The Engle Farm, Coupeville, Washington

The Engle Farm is a former dairy farm cluster on Central Whidbey Island in Coupeville, Washington. The property boasts ten buildings constructed between 1858 and 1936. Nine of the ten buildings are currently vacant and form an interesting intersection for studying mothballing due to their various construction types, building materials, the weather and climate patterns on Whidbey Island and the influence of the National Park Service on the immediate vicinity. Research sought to determine the best methods for mothballing vacant buildings in the Pacific Northwest based on current best practices for our contemporary understanding of ideal environmental conditions for slowing deterioration in historic buildings.;The buildings were surveyed and photographed for existing conditions in August 2015. Buildings are in various states of disrepair and interventions are intended to slow material deterioration until a time that the buildings are again occupied. Mothballing recommendations were devised after analyzing 100+ years of historic climate data recorded on site and interior temperature and relative humidity recorded on a data logger from August 2015-January 2016. Findings concluded that interior temperature is less of a concern in the region because temperature remains mild throughout the year. Interior relative humidity was consistently higher than ideal for historic buildings so interventions are aimed at lowering the RH to an appropriate level and directing water away from the building envelope. The recommendations for mothballing the buildings at the Engle Farm can be tailored to other historic properties on Whidbey Island as well as the four other regions in the world with similar climactic patterns.