Much has been made of mold the last few years, so how does one make sense of it all?  Start by understanding that generally, mold will not grow where the ambient relative humidity is less than 60% or so, and indoor air temp is kept above 65 degrees.  Of course there are exceptions to this, and personal habits play a factor.  There are several things one can do that can help reduce or eliminate the possibility of mold.  These would include :
  • Place a vapor barrier on the soil beneath the house, properly installed and sealed to keep moisture in the soil (indoor air quality or building performance contractor)
  • Provide adequate attic ventilation (roofer)
  • Divert all roof runoff water well away from the foundation so that no water can flow beneath the building (drainage specialist)
  • Install a central heating system that provides heated air (or warmth) uniformly into all habitable rooms (heating contractor)
  • Seal openings through the floor and then properly insulate the floors (insulation or building performance contractor)
  • Provide a fan powered vent in the bathroom, ducted to the exterior, that remains on for at least 15 minutes after bathing or showering, or keep the window open and close the bathroom’s interior door (electrician)
  • Use the exhaust vent in the kitchen when cooking, especially when boiling or steaming or using the oven
  • Wipe down the walls and windows regularly with a mild solution of bleach in water (2 tbs/gallon)
  • Reduce or eliminate any and all sources of moisture (excessive plants, no aquariums), and regularly check that dryers, water heaters and furnaces are properly vented to the exterior
  • Don’t breath while within the house (we typically produce about two pints of moisture per person per day) – just kidding about this one!
As in most all cases of mold, there is no one simple answer to why it occurs in a given place, and not some other places.  Factors that can contribute to mold include any, or all, of the following, with other factors too esoteric to include here:
  • Excessive indoor moisture caused by insufficient bathroom and kitchen ventilation during food preparation or following bathing
  • Improperly, or poorly vented gas-fired appliances
  • Excessive number of indoor plants and watering of same
  • Excessive burning of candles
  • Inadequate and non-uniform heating of interior spaces
  • Lack of proper insulation in walls and floor
  • Excessive moisture conditions in the crawlspace, and/or inadequate sealing of holes and openings in the floor diaphragm (at pipes and cutouts)
  • Northern exposure walls that are not insulated and have poor air circulation
  • Excessive interior furnishing and/or poor or infrequent cleaning of walls, windows and floors
While these recommendations may sound daunting, if you start with the easier or less expensive ones and monitor conditions, then add to the list if mold conditions begin to occur, eventually you will find no mold problems and then you can just maintain.  It seems the “best bang for the buck” might be having an Energy Audit performed by a building performance contractor, who can then recommend the most beneficial steps.

JMC Inspections: Service, Experience, Professionalism since 1982