When the wind blows, roof turbine vents are among the most efficient exhaust vents for removing hot, humid air from attic spaces. The spinning movement of the vent fins, much like a whirligig, creates a sucking action that draws attic air up and out. In order for a turbine vent to work effectively, the roof must have soffit vents installed below the eaves through which cooler air flows into the attic. Older turbine vents may leak because of missing or rusted parts, but if a new turbine vent is leaking, faulty installation is the likely culprit.
Signs of a Problem
Dark damp spots on ceiling drywall are often the first indication that something on the roof is leaking. Finding the leak and repairing it promptly might save the drywall. You can’t always count on seeing the evidence of a leaking vent on the ceiling. Water from a vent leak can run down an angled rafter and down a wall stud, not making an appearance until it drips close enough to the drywall to show dampness. If you’re concerned about an old turbine vent, go outside when there’s a breeze, and see if the vents fins are spinning.
Even slight breezes will cause the fins in a turbine vent to spin. Normally, the force of the air expelled from the attic is sufficient to blow raindrops away from the vent. Each vent fin connects separately at its top and at its bottom, and when the wind is still, the fins close, sealing the vent. Missing fins, or fins that stick open, are an invitation for leaks.
If the turbine vent is operating correctly, the leak might be coming from around the base of the vent. During installation, the roofer will position small sheets of metal counter flashing between the roof’s shingles to divert rainwater down and away from the vent opening. The roofer then caulks around the base of the vent, but caulking can deteriorate or pull away from the vent pipe. When this occurs, incorrect counter flashing will result in leaks.
Repair vs. Replacement
If the turbine vent is old, rusted or sticking, it’s best to replace the whole unit. Finding replacement fins for older vents can be difficult, and if the ball bearings within the vent are sticking, even spray-on lubricant may be only a temporary fix. For leaks from new turbine vents, call a professional roofer who can inspect the flashing around the vent base. Most new turbine vents have sealed ball bearing units that offer years of dependable service.
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