So that’s the perfect example of how the damp runs down the inside of the outer skin of a cavity wall because you’re actually stood in the cavity as it were. Thompson’s or similar is the only answer apart from physical covering. I had two garages like that, in a block when I was a youngster , that I rented from a friend of the sister and another from her neighbor. I kept my beach buggy in one and I had a beetle in the other. I paid two quid a week each but this was back in the late seventies . Anyway, I stopped paying the rent when I started working away and living in a camper . I know both peeps that I rented from moved not long after. I wonder if they’ve cleared my crap out of those garages yet??? Might be worth a torch and look under them doors one evening maybe. Now that would be a a barn find Ozziedog,,,,,,,,, my J U camper was called Puff The Tragic Wagon
I have a new sectional garage to keep the van in ive not noticed any condensation in it but I also have a gap under the door so hopefully that's enough air flow
If the temperature drops below the dew point inside the garage you will still get condensation. My garage has a gap under the door big enough to "post" a 16 amp mains plug under and a vent in the roof apex. In the winter time rainy season cardboard boxes go soft and exposed steel rusts slowly in there.
I just remembered a shed I once had. It had originally been an open fronted farm building with corrugated iron walls and roof. I got condensation when I added doors, but managed to reduce this by attaching bubble wrap to the ceiling.
