Q: My house has soffit vents on the eaves, gable vents on each end of the house and a ridge vent. I live in North Carolina. Is this too much ventilation? Also, should the vents to the crawl space be open in summer and closed in winter?
A: I have received several questions and comments since writing about attic ventilation. The answer to your questions can be found on the website of one of the major ridge vent manufacturing companies. At cor-a-vent.com they state: “The ridge vent should not be used with other roof mounted or gable end vents. They can disrupt the air flow through the attic.”
When you have gable vents, the airflow coming in through the soffit or overhang vents can be disrupted by cross ventilation from the gable vents. The venting works by air entering through the soffit vents, then traveling up each rafter space to exit the roof through the ridge vent. The website also explains how much ventilation is needed: “The ridge vent must have at least an equal amount of soffit ventilation to balance the airflow. There can be more soffit ventilation, but NEVER less soffit ventilation than ridge ventilation.”
For new and remodeled construction I recommend installing a ridge vent and that all the soffits should be made of vinyl and all should be vented. Solid vinyl soffit material costs the same as the vented material. If the home already has a fan, roof vents or gable vents, these should be blocked and sealed from the attic side of the home.
C. Dwight Barnett is a certified master inspector with the American Society of Home Inspectors. Reach him at d.Barnett@insightbb.com.