converted the boxroom into an extra bathroom a few years ago, and have had problems with condensation and mildew to the extent that the paint on the ceiling was peeling off (despite always opening the window after showering) hubby spent many hours scraping off the old paint, coated the ceiling with unibond, then with bathroom emulsion, and also installed an extractor fan which we have on while showering, and until any condensation has cleared afterwards. Despite all this, less than a month later a peeling patch of paint has appeared above the shower.......help!
Dear Slinkycat,I would suggest that you check that you have proper insulation above the ceiling as I was a painter and decorator for many years and poor insulation leads to the ceiling going from hot to cold quickly so causing condensation.
Best of luck,Bilkko