What can be done with walls that are wet and moldy?
Mold (mildew) reproduces quickly. Once it starts growing it travels to other areas via the wind current. Once it lands on another surface it will begin growing there and the cycle continues. Mold requires a food source, the correct temperature and most of all it needs moisture. The recent rain might have something to do with it. Most mildew issues are from leaking areas like windows or pipes. Also, leaking roofs and flooring that doesn't dry could cause the issue. Moisture vapor passes through walls and ceilings and condenses on the surface during the winter. In the short term, I would start by buying or renting a dehumidifier to remove the moisture in the air. You should also get a few fans going to help evaporate some of the moisture. Begin wiping down the affected areas with a mildew remover. Bleach water is highly effective. Make sure you wear a mask. Once all of that is accomplished, I would focus on those areas where the surface is peeling. I would say those are points that have had a lot of moisture for a long period of time. I'm not so sure the answer is to start tearing out walls and running new piping. However, that will depend on what the source of the excessive moisture actually is. If you are going to remodel, consider using primer, caulking and finish paint that are mildew resistant. You could even go with a mildew resistant sealer.