Vinyl siding!? When the devil skates on the lake of fire!Looks like vinyl siding. It is a day late, and a dollar short, but if your walls were wood, the water vapor would pass right through it, eliminating the need for ventilation.
It's 1/2" plywood sheathing with pine clapboard siding over that. New coat of semi gloss paint might be faking you out. And it's open air where the rafters sit on the top plate.
But anyhow... It is all wood construction, and the firewood is seeming very slow to dry.
Hopefully keeping the door open will help a bit.
And for the next batch, I'm splitting it and stacking it outside until next summer.