One small vent is not going to be enough to circulate the air in a well sealed anything. Chuck wet/hot cars in there (especially in the winter) and you will have major humidity issues, to the point where mold will start to grow. Not a huge concern in a detached garage but still best to avoid.
One solution is to add at least one more vent as far away from the current one as possible.
If you really want to get crazy, there is a new product out now (names escapes me atm) where you basically shave off the top to inches of the peak of your roof and you add a cap that runs the entire length of the roof line creating one large vent at the very peak of your roof.
Likely overkill for a garage but ya, your issue is most certainly due to inadequate ventilation.
I guess the easiest solution would to replace the current passive vent with a powered fan variety linked to either a timer or humidity sensor.
|