• Resources Header

    Construction Performance Guidelines

About the Guidelines

These helpful guidelines outline work and material deficiencies in new homes and residential condominium units covered under the statutory warranty [...]

Condensation In Crawl Space

Article Number




Acceptable Performance/Condition

Condensation shall not accumulate on crawl space interior surfaces.


Two-Year - Ontario Building Code Health & Safety Violations. · Damage caused by dampness or condensation due to failure by the homeowner to maintain adequate ventilation is excluded from the statutory warranty.


Adequate ventilation equipment shall be installed in accordance with the Building Code.


Crawl spaces shall be ventilated in accordance with the Building Code. Crawl space ventilation requires careful management by the homeowner to maintain acceptable moisture levels. Typical temporary conditions that may contribute to condensation are: a) at night in unheated crawl spaces, air entering the crawl space gradually cools the interior surfaces of the space. When outdoor temperatures rise the next day moisture picked up by the warm air is carried into the crawl space and condenses on the cool surfaces. b) at night in heated crawl spaces, outside air may rapidly cool foundation walls and provide a cool surface on which moisture in the crawl space can condense. c) if the house is left unheated in the winter, the floors and walls may provide cold surfaces on which moisture in the warmer crawl space may condense. d) stored materials obstruct ventilation airflow. These conditions may not be covered under the statutory warranty.