Help! I Have Icicles in My Attic

Not long ago I received a question from a reader who lives in an older home in the Bristol area. She wrote to me because she had gone to get something that was stored in her attic and noticed that there were icicles hanging off the framing inside. She wasn’t sure how they got there but she was worried and reached out to ask my advice. I’m so glad she did.

It might be hard to believe that icicles can form inside the house, but in many older homes that lack proper insulation and ventilation, the attic can become a magnet for condensation, which will freeze when it gets cold enough and the moisture has nowhere to go.

We all know that heat rises, and when we heat our homes in the winter, a lot of that warm air moves up through our ceilings and into the attic, rising all the way up to where it should be able to pass through the vents to the outside. However, if those vents aren’t working properly, the condensation and air have nowhere to go, so it collects on any cold surface below the dew point and turns into frost. After a while, this frost builds up to form icicles. The more moisture that builds up in the attic, the worse the problem will become. As temperatures rise and that ice and frost start to melt, it can saturate your insulation with water, causing mold and mildew problems as well as potential leaks in your ceiling. What’s worse is this isn’t even just a winter problem. Condensation build up can cause issues in your attic all year long.

So how do you stop the condensation from forming? Your first move is to look for sources that are pushing excess warm air into the attic. If you have a whole house fan, it’s a wise move to cover it as the louvers are letting your valuable heat escape quite easily. Bathroom fans are another sure bet for letting air through and they will cause major condensation issues if they are blowing into the attic instead of venting directly outside. Finally, make sure your folding stairway is covered over with an insulated box or weather stripping to avoid losing that extra heat.

While sealing off places that allow excess heat to get into the attic is a great idea, the one thing you never want to do is seal off your attic vents. Attic ventilation is a system which includes intake vents in the soffit and exhaust vents at the roof’s ridge. If these vents get sealed or blocked, there is nowhere for the condensation to go, so it gets trapped and can easily manifest into a leak. Believe it or not, the average family of four generates two to four gallons of water vapor each day from cooking, cleaning, showering, laundry, and breathing. If that water is left sitting in the attic, you’re going to have a problem.

These freezing temperatures give you a great opportunity to take a look up in your attic to see if you have any frost or icicles culminating in your home. Next week I’ll tell you more about how to properly ventilate and insulate an attic to make sure your property isn’t prone to leaks and other condensation-based damage in the future.  

Bob O’Donnell is the owner of O’Donnell Bros. Inc., a Bristol-based home improvement company established in 1975. Email your questions for Bob to info@odonnellbros.com with the subject line “Ask the Pro.” All questions may be considered for publication. To contact Bob for your remodeling needs, call O’Donnell Bros. Inc. at (860) 589-5155 or visit www.odonnellbros.com. Advice is for guidance only.