I bought a house with a 25' by 14' den (an addition) It has a 12' cathedral ceiling. There's a 6'x3' crawl space above it with no access. New roof with ridge vent. There are 3 A/C vents in the floor(not enough) and one large ceiling fan. On very hot days the higher parts of the walls drip with condensation. The ceiling fan is only on at night. What is causing this? How do I fix it? Please help, nobody else can. Thanks Karlene