A peak roof vent, also called a ridge vent, allows hot air and moisture to escape from the attic via a channel that runs the length of the roof. Peak roof vents are considered the most effective type of attic ventilation, when combined with perimeter intake vents.
The roof ridge is the peak formed when two sides of a sloped roof meet. Roof shingles are applied from the bottom up, so when the roofer hits the roof ridge, there is a gap left over. Ridge cap shingles, which are folded in the middle, are used to cover this gap.
If a roof vent is being installed on a finished roof, the cap shingles must come off before cutting into the roof to install the vents. The most visually appealing method is the shingle-over ridge vent. After the vents are in place, the cap shingles are nailed over the entire ridge line. The ridge vent is slightly tilted downward from the center of the roof to the edges to prevent water from getting inside.
The soffit vents, installed around the perimeter of the roof, are flush with the eaves. These intake vents suck cold air into the attic, so they must not be blocked by insulation. The cold air will push the hot air to the top of the attic and into the peak vents.