The size is 9' x9'. I am not sure were you want to go with outside humidity and temp but I would say about 50 relative and temperature around 21C.The reason I am not sure were you want to go with this info is because I cant change does parameters I need to find a solution for any humidity and temperature.
I will rate above 3 but I was looking for some one in the home improvement section that had knowledge of building principles to explain to me why this humidity and I mean a lot of humidity was being created in this garage.Example is the humidity coming up the floor wall should some building principle be followed. So I am asking you to open this question to such a person
The condensation will be caused by cold surfaces in the room that are below the temperature of the dew point. Think of air as a sponge. When is cools off the sponge becomes smaller and loses its ability to hold moisture. When this temperature drop is below the dew point you get your condensation and thus have wet surfaces. The 2 possible solutions to stop condensation is to constantly keep the temperature above the dew point(heat the space), or remove the moisture from the air, thus raising the dew point temperature. Most people don't choose the heat the space option because it is expensive and uncomfortable. The bets option is to simply remove the moisture.Take care.
Now that was what I was looking for as I said I am an HVAC and was wondering about the theory Good for you I will not only give you above three but a bonus too.