I recently paid a professional builder to completely renew the whole of my flat roof shed. I want to have a freezer & t/drier in there but i notice that one wall in particular is always wet. I have called the builder man back who came to look at it and said that the roof was now 100%. Could this be condensation? It is the wall that seems to get all the weather, and how can i find out if its leaking or just condensation?I cant afford to get another builder in. Any suggestions would be most helpful. Cheers.