Core TradesQuestion 46 of 700
An enclosed attic has 1,500 square feet of area. Using the 1/150 rule with no vapor retarder, what MINIMUM net free ventilating area is required?
a.3 square feet
b.5 square feet
c.7.5 square feet
d.10 square feet
Explanation
Under the 1/150 rule, required vent area = 1,500 / 150 = 10 square feet of net free area. Using the 1/300 rule would give 5 square feet, which applies only when balanced venting or a vapor retarder is used.
Law Reference: 2025 CA Residential Code (CRC) R806 (Roof Ventilation)Practice all 700 questions free — no signup required.
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