Moisture Intrusion
Questions and answers for Moisture Intrusion Observations
Performance Standard: Dampness caused by wicking through the basement walls or floor and condensation of water vapor on cool walls and floor are not the responsibility of the remodeler.
Corrective Measure: None. Dampness prevention is the responsibility of the owner.
Discussion: The owner’s failure to maintain a proper grade away from the house can contribute to dampness. Condensation also contributes to dampness.
Performance Standard: Leaks resulting in actual trickling of water shall be repaired. Leaks caused by landscaping improperly installed by the owner, or by the failure of the owner to maintain proper grades, are not the remodeler’s responsibility. Walls and floors of new construction may become damp as concrete, mortar, and other materials dry, and dampness alone is not considered a deficiency.
Corrective Measure: The remodeler will take such action as necessary to correct basement leaks, except where the cause is determined to result from the owner’s actions or negligence.
Performance Standard: Flowing or trickling water on interior crawl space surfaces is unacceptable.
Corrective Measure: The remodeler will take the necessary corrective measures to eliminate or drain away any flowing or trickling water on crawl space surfaces.
Performance Standard: Condensation in the crawl space shall not result from failure to provide adequate ventilation as required by code. Condensation resulting from other causes is not the responsibility of the remodeler.
Corrective Measure: The remodeler will ensure that ventilation meets the appropriate code requirements. Further reduction of condensation is an owner maintenance responsibility.
Discussion: Temporary conditions may cause condensation that cannot be eliminated by ventilation and a vapor barrier because: Night air gradually cools the interior surfaces of the crawl space. In the morning, moisture picked up by sun-warmed air is carried into the crawl space and condenses on cool surfaces.
At night, outside air may rapidly cool foundation walls and provide a cool surface on which moisture may condense.
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 air may condense.
Excessive moisture inside a heated house may hit the dew point within or on the colder bottom surface of vapor-permeable floor insulation. The condensation can be reduced by placing a vapor barrier between the insulation and the floor sheathing.
If condensation must be entirely eliminated, the owner can do so by sealing and dehumidifying or heating the crawl space, or by heating and dehumidifying the house.