Are ridge vents bad, or do they only cause trouble in certain situations?
Short answer. Ridge vents are not bad; on most gable roofs with open soffit vents they are the most even, lowest profile exhaust you can install. They earn a bad reputation when they are installed without enough intake, combined with other exhaust vents, or used on roofs with very little ridge.
Most complaints about ridge vents trace back to one of a handful of setups, not to the idea itself.
Where ridge vents perform badly
- No intake. A ridge vent has to pull replacement air from somewhere. If the soffits are solid, painted shut, or buried under insulation, it moves little air at all, or it pulls conditioned air up through ceiling gaps.
- Mixed exhaust. When a ridge vent shares an attic with gable vents, box vents, or a power fan, air can short circuit between the exhaust openings and skip the lower attic entirely.
- Short ridges. Many newer North Georgia homes have hip roofs with only a few feet of ridge. There may not be enough length to provide the exhaust the attic needs.
- Unbaffled or cheap vents. Older roll vents and exposed vents without an external wind baffle can let wind driven rain in during the strong thunderstorms Georgia gets every spring and summer.
- Bad cutting or nailing. A slot cut too wide or run all the way to the gable end, or nails too short to hold the vent, invites leaks and blow-offs.
Where they work well
On a gable roof with continuous soffit intake and no other exhaust, a baffled ridge vent pulls air evenly through every rafter bay, has no moving parts, and is nearly invisible under cap shingles. That is why shingle manufacturers commonly recommend it.
How to tell if yours is a problem
Signs of trouble include water spots on the attic floor right under the peak, insulation packed against the eaves, mildew on the underside of the decking, or an attic that stays very hot despite the vent. Most of these are fixable without giving up on ridge venting. Compare the options in ridge vent vs box vents and see why heat matters in attic heat and shingles.