Dead Space Ventilation Requirement

Good day everyone, I have dead space between the house and the addition (garage) that only has an air inlet at the eave but never had a roof vent. I just ripped out and replaced all the decking and there was definitely mold on the underside of the sheathing in that area. It is roughly 14’ x 4’ or 56 ft2 at ceiling height to roof line.

Option 1: Install a roof vent, but I wonder if the 8" roof vent would be too big and create more issues?

Option 2: Make cut outs (covered by air flow grill) on the wall between the studs and let the garage roof vents do the work.

Any suggestions?

Correction: It is only 14" x 2’ or 28 ft2. Apparently it felt bigger when I was crawling in there ;o)


Either one would be a good option.

Im getting the feeling something else is wrong though.
Here in florida
Mold is from an active leak Usually
And sometimes from escaping hot wet moisture blowing into the attic from a bathroom fan.

Oh wait, you could make your intake bigger.
I have this homeowner.
Did his smooth torchdown low-slope roof over 10 years earlier.
It still looked brand new.
He had been alluminum roof coating it as instructed.
No roof vents, only soffit vents.
He had cathedral ceiling and mold was starting to form on each side of the ridge beam.
What had changed?
Just months before
His screens in his soffit had started to rot out
And when he fixed it,
He used a board to hide it for cosmetics.
Which removed over half of his ventilation.

I just told him to bleach both sides of the ridge beam and remove the obstruction to the soffit vents. Done.
And dont forget to tell all your friends, family and neighbors about me because that is how i get all my work.

The air inlet was good and clear. No leaks in that area… many in others… but this one. I live in the pacific north west and it is WET out here for over half the year. I will probably go with the grills on the walls… the double wide could use one less protrusion through the roof ;o)

Thanks for the help… We have friends in Florida, I’ll tell them all about you.