Stop Damaging Condensation in its Tracks February 7, 2013 By Christopher Reynolds
During winter, foggy windows can mean bigger problems. Fix them with these tips.
Condensation on your windows during the cold season might seem like an invitation to draw a picture with your finger—and it is—but that moisture can also be a sign that you’ve got a humidity problem.
Just as humidity in the air turns to water when it meets the cold surface of your windowpanes, water vapor exiting your house through cracks or vents can turn into water that then leaks into your walls. That water can, over time, cause nearly every problem in the book, including peeling paint, toxic mold and a cracked foundation.
Find the Source
Some of the water vapor in your house is naturally occurring in the air, but a good deal of it (up to 18 gallons per week) is produced by you and your family taking showers, doing laundry and even breathing. Since you’re probably not going to stop doing any of those things, you need to get that vapor out of your house before it causes any damage.
Test Your Home’s Humidity
Your first step is to pick up a humidity meter at a hardware store (they’re usually under $10). As a test, if the temperature outside is zero degrees Fahrenheit and your indoor temperature is 75 degrees Fahrenheit, the meter should read 30 percent relative humidity. At any temperature, humidity should stay below 50 percent. If it’s any higher than that, get started on the following right away.
Fix Your Crawl Space
If your house is built on a crawl space, a lot of moisture can come from the dirt floor. A vapor barrier (a thin plastic sheet) should be placed over the entire floor—a roll big enough to cover 700 square feet costs around $75. The space should also be vented, with one square foot of vent per 1,500 square feet of floor space. If you skip the vapor barrier, you’ll need 10 times the ventilation.
Wet concrete walls may be a familiar sight if you have an unfinished basement. This can be caused by moisture coming in and going out. To solve this problem, apply a vapor barrier and insulation to the walls. Or, even better, use rigid foam insulation, which you can glue directly to the concrete and forgo the vapor barrier.
The utility room, laundry room, kitchen and bathroom should all have exhaust vents that take air directly outside. As an example, your clothes dryer produces one pound of water vapor for each pound of laundry—you definitely don’t want that water to end up in your walls. Check to see that your dryer, bathroom and furnace are vented to the outside by looking at the outside of your house, near the room in question, to see if there’s a vent opening. If you suspect that these rooms and appliances aren’t venting outdoors, call in a contractor to take a look. Installing a vent to the outdoors is usually a routine and relatively inexpensive job.
Fix Foggy Windows
Short of replacing your windows or installing bulky storm windows, which can be costly, adding an inexpensive plastic film can remove the chill enough to keep water from gathering. An insulation kit can do the trick, and they’re usually available for under $2 per window.