We had our bathroom remodeled a few months ago. Unfortunately, we opted not to have a ventilation fan installed to keep the costs down. Only a month after it was finished, I noticed a couple of small paint cracks in the ceiling above the tub/shower. It wasn't getting any bigger and we decided it could wait. Now, I noticed the section of wall above the window, which is next to the shower, is starting to feel soft and there is a large paint crack and several bubbles! Can anyone tell me what is causing this and what we should do about it? Appreciate any advice you can offer.