RDH Building Science
    Building Science Centre of Excellence

Control of the indoor humidity in a marine climate is a challenge, especially under operating conditions where high indoor humidity is a norm. Outdated mechanical equipment, inefficient ventilation design, and occupants’ life styles are some of the contributing factors to high indoor humidity. In this field experimental study, the moisture buffering potential of unfinished drywall in reducing daily indoor humidity peaks, coupled with various ventilation strategies are investigated. Two identical test buildings exposed to real climatic conditions in Burnaby, BC are monitored under varying ventilation rates and schemes.

The interior of the test building is clad with unfinished drywall, while the control building is covered with polyethylene, which has negligible moisture buffering. In this way, the moisture buffering potential of drywall under four test cases is isolated. Under the test cases, the indoor air quality in terms of CO2 concentration, and ventilation heat loss of the two buildings are also evaluated.

The results show that the moisture buffering potential of drywall effectively regulates indoor humidity peaks, and maintains relative humidity levels within acceptable thresholds, when coupled with adequate ventilation as recommended by ASHRAE. When coupled with time-controlled and demand-controlled ventilation schemes, the moisture buffering effect of drywall shows competing benefits.

Presented at the 15th Canadian Conference on Building Science and Technology.

View presentation slides here.

RDH Building Science