If a "2.5" car (24x24ft) garage has one roof vent near the top, is there any use in adding an extra roof rent? The garage is unfinished/uninsulated, and there is no obstruction of air between the roof and bottom of the garage. Also consider a Northern Ohio climate (hot+humid summers, freezing+snow winters).
I'm thinking a 2nd vent could help with flow/cross-breeze, but it may also just add to the probability of leaking somewhere down the road.
If a 2nd vent should be added, where? If there were two vent near the top, I feel like that wouldn't do as much as one near the top and the other near the bottom of the roof. But I also think it would look ugly to have a vent that low.
Best Answer
You do not need roof vents for non-insulated open roof garages.
FYI: For attics, the typical ratio is 1:150, so for every 150 sf of space then install 1 sf of venting. You have 576 sf so if you were to need them, you would need a minimum of 5.8 sf total.