By MATT MENKE
I know, water is not exactly what you expect to worry about after summer’s over. Dripping air conditioners are on their way out, but changes in weather do bring condensation to other places we don’t often think about. This month, we’ll take a look at some of the sneakiest spots where water can collect and create problems in our homes.
Windows are the most visible location where condensation can be an issue. Single-pane windows were standard in homes up until the energy crisis in the ‘70s but not all were designed in a way that allowed storm windows to be added. Cool weather outdoors and warm, moist air indoors can cause condensation on the inside of windows. Those water droplets running down into the frame and pooling on the sill can cause steel to rust and wood to rot. Consider adding storm windows, if your windows allow, or upgrading to high-efficiency replacement windows. Your utility bills — and the wall around the window — will benefit from either change.
Condensation between the window and storm window is a different problem. It likely means the small weep holes at the bottom of the window’s outer frame have been painted over. The holes allow water to run out and away from your home. If the holes are painted over, you can drill a couple of small holes just above the sill through the outer frame to get the same benefit without losing insulation value.
Recessed skylights present their own condensation challenges if the light tunnel passes through a cold attic. The tunnel has to be insulated with blanketing stapled around the entire surface; any gaps in the insulation will allow hot and cold air to meet each other, which is an invitation for water to condense in a hard-to-reach spot.
Attics are notoriously musty, and for good reason; they often have inadequate or poorly distributed insulation, often with gaps around plumbing, exhaust vents, wiring and home systems (such as air handlers) that allow hot air from the living space below to meet cold air in the attic. The bathroom vents that exit through the attic expel some of your home’s steamiest air; if they’re not well insulated and run through a cold attic, or if the vent doesn’t fully project sufficiently above the roof outside, condensation can be a real problem. Gaps and uninsulated spots, especially in areas that are exposed to extreme temperature changes, can lead to condensation that may find its way into living spaces below.
Dealing with moisture in a finished basement can be a significant challenge. Moisture normally migrates through the foundation; in an unfinished basement, normal air circulation or a dehumidifier may be all you need to take care of it. But conditions in a finished basement often present challenges that a dehumidifier may not be able to take care of as easily. In the summer, that normal moisture migrating through the foundation meets up with the backside of a wall that encloses an air-conditioned space, and in the winter, warm, moist air in your heated room meets up with the cold foundation. Both of these situations are recipes for condensation problems if the interior wall is in direct contact with the foundation. If you’re finishing your basement, you can plan for this in advance. The best approach is to insulate the back of walls as you install them using a water-resistant insulation like polystyrene or styrofoam that’s covered with a moisture barrier on the back (you may need to add that barrier yourself). Be sure that the insulation isn’t directly against the foundation, though; even a small airspace between the foundation and the interior wall can alleviate condensation issues. The gap also allows air to move and ventilate. If the finished space is the least bit damp and musty, though, running a dehumidifier is essential; retroactively trying to fix a damp or moldy space can be difficult and expensive.
A home energy audit can help identify issues and areas that need attention, and most audits are subsidized and fairly inexpensive. Upgrades and fixes may also be eligible for rebates- a big win for energy efficiency, air quality, and making your home last longer.