Roof Leaks and Mold
When you first look at this picture, it seems that there is just a small amount of moisture damage from a past leak. However, further investigation of the ceiling and wall reveal a serious problem. I was actually called to simply perform a repaint job after the roof had been redone. Unfortunately, the roof leaking was only part of the moisture issue. The edge of the attic was poorly insulated allowing heat in the winter to escape through the ceiling and cause an ice damming issue, allowing water pooling on the roof eaves to flow underneath the shingles and through the roof. This issue is fairly simple to fix by cutting away the drywall on the eave section and insulating the edge with closed cell spray foam insulation. Another issue quickly became apparent. The wall was covered in wall paper. Knowing this could be a can of worms I pealed a small tab back and revealed a completely black back surface of the wall paper. The mold was feeding off the wall paper and the paper from the drywall creating a heavy odor and unhealthy indoor air quality. What was supposed to be a simple paint job ended up being a $1,500 mold remediation, drywall replacement and a $500 spray foam insulation project that was quite messy. However, their problems were solved and will not have to worry about these issues in this section of the house again.
Always remember when diagnosing the cause of an issue to not rule out the possibility of another issue besides the more obvious and apparent ones that are right in front of you. Also, when dealing with mold, most cases are not toxic. However, if you are going to attempt to clean the mold up, you should wear a respirator mask to prevent inhalation of any spores and they can have adverse health affects. But you must make sure that you are solving the problem that is causing the mold and not just temporarily cleaning it up as it will resurface if improperly diagnosed. The example above illustrates this fact.