Originally Posted By: whandley
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1997 UBC 2306.7 Under Floor Ventilation: Under floor areas shall be ventilated by an approved mechanical means or by openings into the under floor area walls. Such openings shall have a net area of not less than 1 square foot for each 150 square feet of under floor area. Openings shall be located as close to corners as practical and shall provide cross ventilation. Where moisture due to climate and groundwater
conditions is not considered excessive, the building official may allow operable louvers and may allow the required net area of vent openings to be reduced to 10 percent of the above, provided the under floor ground surface area is covered with an approved vapor retarder.