If you don’t get it under control, even a small amount of ceiling condensation can quickly leave you with an ugly, blotchy, moldy mess overhead.
The fact that there’s moisture on your ceiling at all is a strong indication your house has problems that are running up your energy bills, ruining your air quality, and stealing your comfort. By taking steps to get rid of that moisture, you can save your ceiling and keep your home more comfortable for less.
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Upgrade Your Attic
The most common cause of ceiling condensation is an attic with too little insulation and ventilation. In an attic like this, wintertime ceiling condensation can form when cold air from the attic hits your warm ceiling. In summer, when the air conditioning is on, the reverse happens.
Improving your attic’s air sealing and insulation prevents attic air from reaching your ceiling, and it’s a fairly easy job to do yourself. Start by checking your attic’s insulation level. If you can see the attic’s floor joints, you need more insulation.
In most parts of the country, an R38 layer of insulation, or about 10 to 14 inches of fiberglass batts, is enough. In a region with cold winters, you might need up to an R60 layer or around 20 inches of fiberglass batts.
Before you install more insulation, seal any air leaks that could let attic air flow to your ceiling. Apply rigid foam insulation to the top of the attic hatch and install weatherstripping on the edges of the hatch. Fill joist spaces with rolled-up insulation batts. If you have a furnace flue, fit aluminum flashing around it and seal the flashing with heat-resistant caulk. Dropped soffits and kneewalls should also be sealed.
Recessed lighting tends to leak air, but it’s tricky to seal. If possible, have your old recessed lights replaced with insulated can models.
Take care of your attic HVAC air ducts, too. Warm air escaping from a duct into a cold attic can create condensation and encourage mold growth. Applying mastic gum to the duct joints and adding an R6 layer of insulation around your sheet metal ducts goes a long way toward protecting your attic and ceiling.
Next, take a look at your attic ventilation. It should allow air to flow both in and out. If your attic has only soffit vents, only ridge vents or a gable vent on just one side, then the space isn’t getting enough airflow. Although many attics do well with a ridge-and-soffit ventilation system, this system isn’t ideal for every home. Designing effective attic ventilation is something of an art, so it’s best left to a professional.
Get a Handle on Your Indoor Humidity
The attic isn’t always to blame for ceiling condensation. Sometimes, your daily activities add more humidity to the air than your home can handle, leading to a buildup of moisture. If you notice condensation on your windows and walls, find peeling wallpaper or bubbled paint, or see mold spots around the house, your home’s humidity is too high.
To find out how serious your humidity issue is, hang a hygrometer on your wall. An indoor humidity of between 45 to 55 percent is ideal, but anything higher will cause problems.
Start reducing your indoor humidity by always using lids on pots when you cook, making your showers shorter and cooler, hanging laundry outdoors to dry, and running your exhaust fan for 10 to 15 minutes after cooking or showering. Make sure your clothes dryer vents to the outdoors and not into your laundry room or crawl space. Containing all your houseplants to one room and keeping less firewood indoors can help, too.
Backdrafting exhaust fumes from gas or other fuel-burning appliances can also contribute to moisture problems, not to mention potentially fatal carbon monoxide poisoning. Leaky HVAC air ducts, large exhaust fans or range hood fans, and a blocked or oversized flue are all possible causes of backdrafting.
Let Your Home Breathe
If you’re already doing what you can to put less moisture into the air, it’s time to look into improving your home’s ventilation. Lack of airflow indoors can cause moisture to build up until it eventually starts clinging to the walls and ceiling.
To improve your airflow, you have several options for whole-house ventilation systems. Central exhaust systems, which draw air out of your home, are favored in dry, cold-winter climates where there’s less risk of the house drawing in humid outdoor air. In warm, humid climates, a supply system is preferable because it gives you a chance to dehumidify the air coming in. A balanced system, which brings in fresh air and draws out stale air, is well suited to any climate, but installation can get pricey.
Regardless of type, a whole-house ventilation system requires professional design and installation because if it’s not working properly, it can make your humidity and condensation problems even worse.
For a ceiling condensation problem in just one part of the house, such as the basement or bathroom, consider bringing in a portable dehumidifier. If you live in a humid climate and nothing you do seems to reign in your indoor humidity, your home might be a good candidate for a whole-house dehumidifier.
If you’ve spotted ceiling condensation recently, first make sure your daily habits aren’t raising your indoor humidity levels. Then check the condition of your attic to see if lack of insulation and ventilation could be causing your problem. Finally, look into improving the ventilation in your living space.
The home improvements you can make to get rid of ceiling condensation all have benefits for your home’s energy efficiency and your comfort, so they’re well worth the investment.