!HELP! Pole Barn Mold

[tizken]

What usually happens at my shop is the building stays cool inside due to insulation and a white roof. When it warms up outside the humidity goes up, that air when cooled to my inside temperature will condense on everything.

If you take 70 deg air at 60% RH and just change the temperature to about 55 deg that air will become saturated, to the point that it will create clouds in your building. Venting more of the same air into the building will not help, you need to either warm up the building or remove moisture from the air and keep the place sealed up. This is a downside to insulating the building well, the sun dosn't heat it up fast enough to make up for the weather changing in the spring.

Look up a Psychometric chart and you can see what I am talking about.

 

[stillnostrebor]

I did not do the math on my 1,200 square foot building, that is built very similarly to the OP's, but when I had almost the exact same problem I bought a big box store dehumidifier that could be set up with a drain hose. I set it up on a shelf and plumbed it out a wall and fired it up. It took almost a week to stabilize the building, and it will hold it at 45% RH no problem.

This was almost 2 years ago and it has ran strong in SW Missouri humid summer weather. At least until yesterday, when I unplugged it after finishing my minisplit install.