Advice needed. Basically I have an old stone wall house. I have terrible trouble with condensation forming in bedroom. Tries leaving window open, dehumidifier, air brick and all the rest but to no avail. Decorated room 6 months ago. Great till last month - paint has now started blowing off 2 external walls. Walls are running with condensation. What on earth can I do - this room must have been decorated about 6 times in as many years. Whatever I do just doesnt work. Spent a fortune on Zinsser paint last time - that didnt work. This is def condensation and not damp. Please help before I take a sledgehammer to the bloody wall. It is costing me a fortune.