How far should a ridge vent be from the end of the roof at each kind of ridge end?
Short answer. The deck slot under a ridge vent typically stops about 6 inches from a gable end and about 12 inches from walls, chimneys and intersecting ridges, per most manufacturers' instructions, while the vent material itself usually runs the full ridge for a uniform look. The right stopping point also depends on what is below: the slot should only open over attic that has intake feeding it.
End condition by end condition
- Gable end with a rake overhang: the slot stops short of the end, and on overhangs it makes sense to stop it inside the line of the gable wall, since the overhang has no attic below to vent.
- Ridge running into a second story wall: stop about 12 inches back so the vent does not sit in the splash zone where water and wind come down the wall.
- Ridge meeting a chimney: similar setback, and the cricket and flashing behind the chimney take priority over vent length.
- Ridge ending at hips: the slot stops before the hip intersection. Hip caps lap over the vent end.
- Ridge continuing over a porch or vaulted room: stop where the vented attic ends. A slot over a porch ceiling or sealed vault vents nothing and adds a leak path.
Why the vent still runs to the end
Most roofers carry the vent the full length so the ridge line looks even, then seal the ends with end plugs and cap shingles. Over solid deck, that extra vent is just a raised ridge cap.
Measure from the right place
Instructions measure from the end of the ridge or from the obstruction. Each product sets its own numbers, so the printed sheet for the vent on your roof is the final word.
Signs the slot runs too far
Water stains at the top of a gable wall inside the attic after windy storms, or wasp nests at the ridge ends. See wind damage to roofs in Georgia and roof anatomy explained.