Should I ventilate an unheated garage attic?

An unheated garage attic is not treated any differently than an attic over a heated and conditioned living space

An unheated garage attic is not treated any differently than an attic over a heated and conditioned living space. While it is true the amount of moisture generated inside the garage is less than the amount of moisture generated from a living space, car exhaust inside a garage can cause problems. When cars idle for extended periods of time inside the garage the built up moisture can begin to condense under the roof deck. Additionally, if the garage is shingled, the shingle manufacturer will require that the roof deck be ventilated.