Musty Smells – Q & A

My house smells musty, especially in the summer.  Is this because of mold?

The short answer is maybe.  It could be any number of things.  Trapped moisture in the house can jump start some funky smells.  This will take a little detective work on your part and a general understanding of how your house breathes.

Homes were designed to keep out the elements so people could be comfortable, safe, and stay healthy.  Wood framed homes became the most economical and versatile way of building a small home in modern times.  As demand for more energy efficient homes came into vogue in the 1970’s, builders responded with tighter construction methods.  They installed thick insulation with continuous vapor barriers, airtight windows and doors, house wrap and EPS foam on the exterior, draft stops, caulking, and weather-stripping everywhere, even behind switch plates.  Building science was in full trial and error mode with new materials and methods.  Words like “super insulated” and “air changes” and “R-value” became common in the industry.

Problems started showing up a few years later because the homes were built too tight. Insulation in wall cavities can become soaked with trapped moisture.  Most of this moisture comes from everyday living; boiling water on the stove, bathing, washing clothes and dishes, and even breathing.  Moisture can be from a damp basement floor and some of it from leaks.  Now this trapped moisture cannot escape.  Mold may start to grow.  The industry is still coping with the problems of mold today.  New products like Heat Recovery Ventilators (HRV’s) and companies specializing in mold remediation are attempting to control this persistent health issue.

Staying on top of moisture and humidity issues will help keep it in check.  It may also help to prevent carpenter ants and termites from nesting in damp wood.  Use air conditioners or dehumidifiers when necessary.  Disposable calcium chloride-type desiccants work well in crawl spaces and small areas year-round.  Make sure the kitchen, bathroom, and clothes dryer are properly vented to the outside.  You don’t want the exhaust ducts dead-ending in the attic.  If you have one, use your whole house fan to dry out the walls and circulate the air.

For minor musty issues, it helps to pinpoint what is causing the problem.  For example: musty smelling clothes can be caused by bacteria spreading in the washing machine.  The dryer does not kill it.  It may be as simple as disinfecting the washing machine with a hot water and bleach treatment once in a while.  Try washing a white load with bleach as the last load for the week and the machine should stay clean.

It is always important to identify leaks immediately and repair them before it turns into a problem.  Something as simple as not overwatering a plant can help to prevent this.  It is much more cost effective to address a leak or moisture problem early on, than to have to rip out drywall or flooring and start over.  If you have obvious mold issues that are too big to tackle, get it inspected by a reputable environmental clean-up firm.  It is not worth jeopardizing your health.