Moisture Control


Got Ants? Maybe it’s something in the water.

When ants make a raid on the kitchen the only thing you want to do is get rid of them.  Unfortunately, getting rid of them isn't nearly as important as, why are they there? What made your home the place to live?

Even though they can survive just fine in our cold climate, the most common ant invaders have two things in common, they are attracted to temperatures between 80 and 90 degrees and humidity between 80 and 90 percent.

Now you are probably wondering, where are they going to find those conditions in western Washington? Surprisingly, even on a cool day a flat rock setting in direct sunlight will do quite nicely.

In our homes there are many places where these conditions can occur but the kitchen and bath rooms are the most vulnerable.

Cook dinner and run the dish washer and, presto, 80% humidity.  Add a transformer for the phone or appliance and voila!  Habitat no ant can resist.


Take a shower and steam up the mirror, ta da, 80% humidity.  Add a night light for a bit of extra heat and, sha-zam, ant condo in the wall socket.

Its that easy.

Condensation is another way moisture can build up in your home.  A one degree drop in temperature raises the moisture load in the air two and a half percent.

A typical home with the thermostat set at 60 degrees with 70% humidity will condense moisture on any surface that is 45 degrees or below.  Window sills are particularly vulnerable to this kind of moisture and on sunny days this moisture will flash off creating the high temperature & humidity ants love.

There are several systems built into your home to control moisture, some you see every day others you wont see without remodeling your home.

Because heat rises, your house literally acts like a chimney sucking on the ground.  For that reason all new construction has a layer of plastic installed over the soil in the crawlspace.  One square yard of exposed soil under your home can release 2 quarts of water vapor a day into the structure.

The building envelope (roof, walls, floors) is a passive system made of multiple layers of material to protect against moisture entering and a system of vents to allow moisture to escape.  It also has seals and caulk to stop air infiltration and insulation to prevent condensation on the inside of your home.  Assuming your home was assembled correctly, these elements require little or no attention short of keeping them in good repair. (paint, caulk, roofing).

The rest of the systems are active, like exhaust fans, dryer exhausts, and range vents designed to carry saturated air directly outside.  These devices have to be vented to the exterior of the building not into the attic or crawlspace and they are usually fitted with screens or filters that need frequent cleaning to prevent them from getting clogged with dust.  Bathroom fans and range fans must be used consistently to avoid moisture build up.

Your heating system is also a critical element in the control of moisture in your home by heating and drying the air.  With forced air heating you can often have it set up to operate with a slight positive pressure which forces moisture out of walls and even reduces dust drawn into the building by the chimney effect.  (Don’t attempt this without professional help. Negative pressure can make the problem worse or cause gas appliances to back draft.)

In these energy conscious times its tempting to turn the thermostat down but below 58 degrees you run the risk of condensation and mildew.  If you turn the heat off for extended periods during cold weather you can get huge moisture loads in dry wall, timbers and furniture and risk doing serious damage to your home.

Even armed with this information you may still have moisture problems.  You should get professional advice if you regularly encounter mold or mildew and the ants may actually be the good guys shouting, “HEY! The water is over here!”

Ant Facts

800-300-2752

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