What is the vent on top of my roof, and should rain get in it?
Short answer. The vent on top of most roofs is an attic exhaust vent, either a continuous ridge vent along the peak or box vents or turbines near it, and its job is to let hot, moist attic air escape. It is designed with baffles, louvers and flashing to keep normal rain out, so water in the attic below it usually means damage, a failed seal or an installation problem.
Should you cover it?
No. Covering a roof vent for winter, for a storm or to stop drafts blocks the attic's exhaust and traps heat and moisture. The one exception is a short term emergency, such as a vent torn off by wind, where a tarp keeps rain out until the repair.
When rain does get in
- Wind-driven rain: in strong thunderstorms, unbaffled or older vents can admit some water.
- Cracked hoods or dented louvers: often from hail or falling limbs.
- Failed flashing: a flange laid on top of the shingles and caulked instead of tucked under the course above.
- Lifted ridge caps: missing nails or short nails after high winds.
- Condensation: water below a vent after a cold, dry night may be condensation rather than rain.
After a storm, check
- From the ground with binoculars, look for dents, cracks, missing caps or missing vents.
- In the attic, look for fresh stains or wet insulation under the vents.
- Photograph anything unusual and note the date.
Dented metal vents are one of the easiest signs of hail to spot from the ground. Check recent hail near you at North Georgia Hail Map, and read Georgia hail season and wind damage to roofs in Georgia. Robust Roofing outlines its storm process on its storm damage restoration page.