An older home with a ‘breathing’ problem
Q. A year ago, we moved into an old rental house that had been remodeled. Subsequently, we have had respiratory problems and can smell mold. It’s worse in the morning. The house has no kitchen vent, no bathroom vent and crawl space vents, and only one vent for the attic. It also concerns me that the gutters do not carry the rain away from the house. It pools up around the house and seeps in around the foundation. How do I argue this with the landlord? Or should we just move?
A. Older homes were usually built to “breathe.” As I understand it, all of the air inside the homes should be naturally replaced with fresh outside air at least once an hour. Air leaks at window and door openings, through openings or cracks in exterior walls and in the ceiling and floors allowed the air exchanges to take place and mold was seldom a problem in these older homes. It was during the fuel-shortage crisis of the 1970s, when homeowners began to seal and insulate their homes to save energy, that indoor mold contamination became a noticeable health issue. Even an older home could become musty if the windows and doors were covered and the home was abandoned.
Attics need proper ventilation to transfer moisture from the home to the air outside. A crawl space can be either vented or unvented, but recent studies suggest an unvented and conditioned crawl space is preferred. You can find a treasure trove of information on crawl spaces at www.buildingscience.com/resources/cond-crawlspaces.
Gutter and drainage problems, which allow water to pool next to the foundation, help to feed mold spores that are naturally present in the wood floor system of the crawl space. The damp crawl space also has an impact on the attic. As the moisture in the crawl space evaporates, it travels through the home, ending up trapped in the unvented attic where it will feed additional mold spores.
Mold spores are always with us in a wood-frame structure, but it is our responsibility to prevent the mold from growing by reducing the moisture levels in and around the home. Properly grade and drain water away from the foundation, cover the crawl space floor with a vapor barrier, provide cross ventilation for the attic and install exhaust fans for the kitchen and bathrooms. Lower indoor humidity levels and the mold spores will go dormant.
Ÿ Dwight Barnett is a certified master inspector with the American Society of Home Inspectors. Write to him with home improvement questions at d.Barnett@insightbb.com.
Scripps Howard News Service