The most common issue in a bathroom is the fact that they have no or very poor ventilation, and thus become susceptible to mold growth. The location of an exhaust fan is also crucial, as most are located in the center of the room. This causes the steam from a shower to have to make it way around the room before having a chance to be exhausted. By that time, there’s too much steam and the build up is more than the exhaust can handle. Other times, the exhaust itself is too small or doesn’t function properly. In bathrooms that have these issues, or in cases where you may not even have an exhaust, the excess steam will eventually cause mold and will require remediation. Even if mold remediation is performed, if the ventilation issue is not corrected, the mold will once again return no matter what paint or other building materials you use. So, to avoid this type of mold issue in your bathroom, you have to have proper exhaust and it should be located right above the shower.