Here is a Mold 101 video, showing what has happened in an actual house, how to fix it and how to do it right to begin with. Matt Risinger, master builder takes on mold growing on the walls of a basement in this video. Any time you see mold in a house, mold needs three things to grow—the right temperature, a food source and a water source. The paper of drywall is an ideal food source for mold to grow. It needs an elevated temperature, unfortunately mirroring the temperatures that we like…it likes them too. The water source is actually the biggest thing that can be controlled. In the house featured in the film, the problem is an elevated humidity. The walls are underground in this space and there's a walkout to outside and the weather has been very wet. Humidity in the room is approximately 70% and anything over 60% spells trouble. First thing added was a dehumidifier, bringing the humidity all the way down to 41%. Risinger looks at the house as a whole to see what else might contribute to mold growth. Further investigation, beginning in the attic, shows that the staircase going into the attic does not have weather stripping or adequate insulation both causing a variety of issues, potentially adding to the problem in the basement. Upgrading filters on the house also filer out allergens and mold spores that easily escape inferior filters. In addition, air sealing completes the "fix" on this house and its underlying mold problems and air quality issues. Check out the video"," it's hard not to have multiple takeaways from this one.