What if a ridge vent doesn have an external baffle?
With an unbaffled ridge vent, wind and other elements can blow directly in through the ridge vent. Air entering the vent can create pressure in the attic, which prevents air and moisture from being pulled out. Also, stronger winds can actually pass through one side of the vent and out the other, which also prevents air and moisture from escaping the attic. Tests show that externally baffled vents outperform unbaffled ridge vents.
Curling is when the corners of shingles turn up and it is generally caused by excess moisture attacking the underside of the shingle. Inadequate ventilation causes the entrapment of heat and moisture in the attic. This will eventually penetrate the roof deck and cause the shingles to curl. Improving air circulation within the attic space can stop the progress and rectify the situation if the curling is not too severe.
