Wet threat: Out, out, damp spots!

Larry Sambrook

Certified Indoor Environmentalist of Airflow Diagnostics Institute, LLC

Q: I read all about mold problems in a recent issue of The Hook. What can I do to safeguard my own house against moisture intrusion? How can I tell if I already have a problem?–Dampened Spirit

A: Moisture intrusion is a year-round problem that can strike anywhere, but it's typically worse in the summer because of the increased humidity.

If you have a crawl space, the best way to prevent moisture problems is to make sure it's properly protected from water. The crawl space is the space between the ground and your house. (Houses with basements don't have one.) The crawl space should contain overlapping layers of plastic, taped at the seams and glued to the wall of the house.

Moisture can invade your home whenever there's dirt in the crawl space (which is almost always). For an average 1200-sq.-ft. house, about 13 gallons of moisture vapor per day seep up from the ground, no matter the house's location. The moisture in the crawl space then gets into wood, causing mold and wood deterioration.

Another element to consider when you're dealing with moisture intrusion is poor heating and air conditioning. These air systems have supplies and returns. Supplies provide the cool air coming into the house, and returns push the inner air out. Without enough returns, the house will gradually pull humidity in through the walls. A homeowner should have a return in every room, with the exception of the kitchen and the bathroom.

You can tell if you have a moisture intrusion problem if the air inside your house feels damp or if you spot any mold growth. Good places to check are the grilles on the air vents of your home and the walls of the bathroom.

If you've confirmed that you have a mold problem and you're unable to remedy it with the suggestions listed above, it's time to call a professional. Although costs vary depending on the size of the house and the seriousness of the problem, a professional should be able to perform a whole house dehumidification for a 2500-sq.-ft. house for $4000-4500. This procedure involves using air to push out on the walls of the house from the inside. Ideally, a building should be positively pressurized or neutral so that it's not sucking humidity through the walls.

This problem is a common yet serious one. Although a healthy adult may not immediately be affected, mold can be detrimental to the health of small children whose respiratory systems are still developing, anyone on chemotherapy, and elderly inhabitants. Resulting medical issues can range from asthma to cancer.

Damage to the home can be severe, as well. If it gets to the point where the wood has over 28 percent moisture content, it will begin to rot, eventually causing the house to collapse.

Although there are 1.2 million different molds, the treatment for all of them is the same: remove the moisture on which they thrive. It's a straightforward procedure, but an important one if you're experiencing moisture intrusion.

Larry Sambrook of Airflow Diagnostics Institute