Also as Bill suggested make sure you have a proper vent fan with exhaust, venting to soffit though is last resort in our area ( north east ) due to sending warm moist air out which gets blown back up into the soffit and creates mold and moisture issues on the underside of roof deck.

Cultural area of Japan, tons of UNESCO World heritage listed sites, high barrier entry (less competition), shortage of hotels, lower penetration of China and international buyers.

You may very well need a sump pump, depending on how much moisture.

We are replacing the gypsum board and using a fairly expensive system to replace the moisture barrier and insulation.  

Seeing that flashing was not installed, you have water penetrating between the gaps. 2nd photo shows concrete spalling (most likely due to freeze-thaw cycle) and exposed rebar now beginning to rust.

What's interesting is that the inside of the shed roof is in pristine condition with no penetration of the rust from the outside...yet.My goal is to preserve the shed from further deterioration.

this keeps moisture and wind from coming into the house. you will have a tough time removing and putting anything back. i would recommend trying to treat it.

You could have moisture issues, which will shorten the life of the paint, and even if you don't, it has to be repainted at some point indefinitely.

Phillip:We use a variety of liquid, moisture, and humidity sensors with our building monitoring set-up to detect leaks (or when a bathroom fan or the HRV needs to be switched on) and have begun incorporating them into our renovations.That said, with the exception of humidistats on bathroom fans, the best offence we've found is prevention.  

I want to try to penetrate the area with some multi family rehab projects.