Mold and moisture issues are a pretty common motivation for homeowners to give us a ring. There’s condensation on the windows, water dripping into the window box. One homeowner described how if they opened their front door during the winter, the glass panes on the storm door would fog up within 10 or 12 seconds. Structural issues in the house, like dirt/mud floors in the basement, sometimes cause the problems but often it is caused by owner behavior.
Energy Audits and Water Sports
One of my original audit instructors called this ‘water sports’. These are home owner activities that add a load of moisture into the building enclosure. This can include inadvertent issues like dryer or bathroom fans vented into the house. They can be integral features of the house like a jacuzzi/hot tub or an infinite pool. Or it can be individual habits and hobbies like long showers, cooking a great deal (boiling water), storing firewood indoors or owning lots of plants or an aquarium.
Mold, Molder, Moldest
Mold is one of those homeowner black triple-X no-no’s bound to spook most owners. It’s the harbinger of so many other problems: wood rot, ants, bleu cheese dressing…the horror. Mold has catapulted up the home’s biggest problem list over the last couple decades for a few reasons.
Building Science Corp wrote this great article a few years back detailing the reasons (so I don’t have to!): Modern houses uses materials with a much lower moisture content (thus have a much lower capacity to absorb excess moisture), they use more processed materials like OSB and engineered I-joists which are easier for mold to eat and lastly that houses are much tighter with much less heat, limiting drying potential. One other tremendous change has been in how people introduce water and humidity into the building.
Unlike some big breezy Maine farmhouse heated with 8 cords of firewood dry blasting out the building, a tight modern house is much more susceptible to moisture and your personal water sports.
Mold is a Water Issue
A recent audit customer called because they were having condensation and mold crop up everywhere in the house. Opening the front door was like walking into a greenhouse. The relative humidity was over 70%. Many of the windows were fogged up on a relatively temperate day. If one opened the kitchen door, the glass on the storm door steamed up almost instantly. It was pretty damp.
It took all of three minutes to discover the source of the humidity. The homeowner and his wife loved fish and had at least 15 aquariums. They had several open tanks through the house, salt and fresh water with a menagerie of sea life. It was also clear from the passion with which they spoke of their aquatic buddies that it was an integral part of their home life. Eliminating that source of moisture was not an option? So what to do?
How does one reconcile what a homeowner wants and what building science dictates? After discussing some option, they were open to making one room a dedicated ‘fish room’ with some ventilation and environmental controls.
Mold in homes is a function of moisture and the capacity of a house to handle that moisture. If you’re having problems with mold, look to the moisture. Reduce your water sports and you’ll reduce mold issues.