What are the most common ridge vent installation mistakes, and how do you avoid them?
Short answer. The most common ridge vent mistakes are a slot that is never cut, cut too narrow, or cut too close to the ends; nails too short to reach through the deck; crushed vent from overdriven nails; missing end plugs; other exhaust vents left in place; and no soffit intake to feed it. Each one either kills the airflow or invites leaks, and all are avoidable by following the vent's instruction sheet.
Slot mistakes
- Never cut: the vent goes on but the deck under it is solid. Looks vented, does nothing.
- Too narrow: chokes the vent below its rated net free area.
- Too wide: the vent no longer covers it fully, and nails lose solid deck.
- Too long: running into the gable ends or right up to walls invites wind-driven rain.
- Felt left over the slot: underlayment run across the peak and not cut back.
Fastening mistakes
- Nails that only reach the vent, not 3/4 inch into or through the deck.
- Overdriven nails that crush the vent and dimple the caps.
- Nails outside the vent's marked nailing zone.
Finishing mistakes
- Missing end plugs.
- Cap shingles that do not match the vent's width.
- Caps installed facing into the prevailing wind.
System mistakes
- Box vents, turbines or a fan left on the same attic.
- Gable louvers left open beside it.
- Soffits blocked by insulation or solid backing.
- A slot cut over vaulted areas with no attic below.
How to check a finished job
From the attic, look for a continuous line of daylight that stops short of the ends, with nail tips showing through on both sides. From outside, a straight, even ridge with no exposed vent edges. See ridge vent vs box vents and how to choose a roofing contractor in Georgia.