Condensation in Attic in Winter

Truck in front of a house

Condensation in the attic in winter is a common issue. Nonetheless, it can be a nightmare to deal with. Chances are that you do not enter your attic unless it is to store old items or seasonal decoration. It makes spotting condensation in its early stages quite difficult.

Typically, attic condensation occurs during the cold weather. If left unchecked, condensation can cause serious problems in your house, i.e., mold, rotting, and much more. To avoid this, you must understand what causes condensation and how you can cure your condensation problem.

Above the Rest Roofing and Siding, a CT Roofing expert, weighs in on the topic.

Why is there condensation in the attic in winter?

Condensation occurs when the air consists of substantial amounts of moisture. Now, if the moist air were to encounter a surface that cools the warmer air to a temperature below its dew point, it forms moisture through water droplets. These appear atop your cold surface, and the overall process is condensation.

Similarly, when the warm air of your attic touches a colder surface, it causes condensation. It means condensation occurs mostly in the winter or spring months.

 If you do not catch condensation in the early stages, it can cause your timbers to rot. Other than this, your loft may experience the growth of mold in the form of small black dots, fungi, and wet or dry rot.

Normal vs. Excessive Condensation

It is easy to confuse traditional condensation with excessive condensation; here, we discuss how both are different.

Your loft space is bound to create a certain amount of condensation during a cold wave. Moreover, the lack of wind through the vents increases condensation in your attic in winter. But here is the thing; normal condensation clears with the rise of temperature and increase in winds.

On the other hand, excessive condensation occurs during a considerably warmer time. Plus, you will notice it will not clear with the change in weather. Not to mention, excessive condensation can lead to troublesome results, aka a damp, stale, and moldy attic that features obvious fungal growth. Your timber and roof may end up rotting as well.

Is it Condensation or a Roof Leak?

On the flip side, finding the solution to your moisture problem majorly depends on accurately identifying the ‘leak’ in your house. Here we have compiled the three possible reasons behind your house leaks:

If your house boasts low-quality installation of shingles or flashing details, rain may enter your house through the roofing. In this case, you will want to learn more about your roof leaking in winter. A damaged windowsill or bad siding installation may cause it as well.

The snow accumulating on your roof may start melting because of warm air reaching the attic. In turn, it causes ice buildup, which leads to air leakage.

Last but not least, condensation in your attic or frost buildup may lead to a leak in your house. Reduce the development of condensation to eliminate leakage.

How Does Condensation in Attic in Winter Occur?

You will have a hard time finding the root of your condensation problem if you do not know how it occurs. Following are ways condensation may occur in your house:

In Lofts After Insulation

Typically, modern attics that have recently undergone insulation installation often notice condensation. While insulation can help save cash and make your home warmer, it can also restrict your house’s breathability.

Condensation in your attic in winter can be caused by too much insulation and not enough airflow

It means that moist air will start accumulating in your house and, ultimately, it will encounter the cold roof tiles and result in condensation. All in all, homeowners, and contractors both should recheck loft insulation to ensure adequate installation.

In Newly Built Properties

Another recurring problem leading to condensation is wet trade building material. Cement, plaster, and mortar, when blended with water, it releases substantial amounts of moisture into the air as it starts to dry. The moisture from the process meets a cold surface, and thus, condensation occurs.

Therefore, it is vital your new building is well-ventilated. Plus, make sure no sign of condensation appears during the first year of your residence.

In Un-Insulated Lofts

If your house boasts a poorly insulated loft hatch, it will let warm air enter your attic. Moreover, the lack of breathability will allow for the buildup of said moisture-laden air.

When this warm air collides with cold roof slates, etc., the air starts condensing. Next comes the stream of water down your roof to make a mess in your attic.

In Poorly Designed Buildings

Modern buildings boast an innovative design featuring eaves and ridges that ensure moisture-laden air escapes your house. However, comparatively older buildings utilized low-quality tile vents, or they did not include one at all.

On the other hand, homeowners block ventilation by placing their possessions and boxes in their lofts. Once the air is unable to circulate, condensation starts occurring. Worst of all, here, it may be undetectable, meaning mold and rotting is likely to occur without your knowledge.

If you are present during any roof replacement or repairs on your home, pay attention to the craftsmanship that was used. It is critical to identify signs of a bad roofing job early.

The Attic Has a Hot Water Tank

A common occurrence in houses is that their hot water tanks are in their attics. If your house also boasts that, it is vital you check and analyze its activity to ensure it does not release steam in the loft.

Ways to Determine Your House Has Condensation

If undetected, condensation can cause a variety of terrible repercussions. Here is how you can catch condensation in your attic:

  1. First and foremost, ask yourself; is it condensation?
  2. Attic condensation occurs mostly on the underside of your sheathings.
  3. Moreover, it typically begins generating on nails penetrating the sheathing. If they are rusting, it means your house is experiencing condensation.
  4. However, if you notice moisture accumulation around the roof valley or penetration, it is not because of condensation.
  5. Lastly, look for drip marks on the attic floor.

Other than this, be on the lookout for:

  • Sagging ridgeline
  • Water leaks on either the interior walls or ceilings
  • Drooping ceilings
  • Jammed doors
  • Cracked or broken interior walls
  • Creaking and squeaky noises


How to Reduce Moisture in Your Home? 

Attic condensation in winter is a challenging task to deal with it. Prevent it from occurring by reducing moisture in your home. Here we have rounded up tips to help reduce moisture in your house.

Run Exhaust Fans in Your House

Your kitchen and bathroom come with high-quality exhaust fans to eliminate odors and humidity. However, it will be useless if the exhaust fans and dryer vents discharge into the attic space. Here, the fans will start dumping excess moist air into the attic while inevitably leading to condensation.

Here is a great video by Studio Gertrude that explains how to inspect your bathroom exhaust fan for issues.

Not to mention, an in-depth study suggests that humidity levels above 55% can lead to the growth of mold and bacteria. Thus, it would be best to turn on the exhaust every time you start cooking or take a shower.

Using a Dehumidifier

An inexpensive yet super useful way to control the humidity in your house is installing a dehumidifier. Especially if the humidity levels inside your home remain at or exceeds 65%, using a dehumidifier will do wonders for your house.

Grow Plants

Reduce moisture in the air by growing plants that help eradicate moisture. Plants such as the Boston fern helps lower humidity levels. Not to mention, you upgrade your environment by allowing the plant to add oxygen to your house.

Condensation in attic during winter can be helped by placing more plants in your home.

Ensure Your Attic is Well-ventilated

An extensive study shows that keeping your attic’s temperature under freezing when the outside boasts one lower than 20 can reduce ice dams’ chances of formation. Now, if you want to keep the attic cool, you will need to ensure proper ventilation.

In turn, your attic will stay adequately cool and will not experience moisture buildup.

Substituting Carpets

It may sound unlikely, but the fact is that carpets retain a substantial amount of moisture. While these offer a soft, cushiony surface to enhance the beauty of your house, they also add to the room’s humidity.

Not just this, but there is a slight chance your dehumidifier may not be highly effective. In this case, you will have to replace your carpet.

How to Cure Condensation in Attic in Winter

First and foremost, to reduce condensation in your attic, you need to improve the overall ventilation. Typically, condensation occurs as a result of warm air colliding with a cold surface.

However, allowing your house to breathe eradicates the chances of condensation occurring.

Start by checking whether your attics insulation is pressed under the eaves or not. Next, make sure your contractor adequately installed your roof vents. The goal here should be to receive proper ventilation in the winter season and restrict warm air entrance during the spring months. Lastly, you may check whether or not your house has boxes stored in the attic.

Fix Leaks or Cracks

Inspect your roof carefully to locate any existing leaks and cracks on your roof. If there are any, make sure you get them fixed instantly to eliminate air leakage into the attic space.

Condensation in attic in winter can be caused by roof leaks and faulty shingles.

Enhance Your Roof

Older roofs are susceptible to allowing moisture inside the house due to poor quality installation. Thus, it would help if you swapped it with a more effective vapor barrier. While it is a somewhat long process, it is worth it since you will not have additional issues later.

Moreover, consider opting for a warm roof that ensures dual benefits, as well as protects your loft space from condensation while remaining warm.

Reduce Moisture in Your House

Reducing manual moisture is a great way to slow down condensation in your attic in winter. From installing extractor fans in your restrooms and kitchen to keeping hot tanks away, you can reduce moisture accumulation in many ways.

In fact, an in-depth study suggests that drying clothes inside the house can spike moisture levels up by 30%.

Insulate Your Roof

You can insulate your roofs in two different ways:

DIY It

Your first option is to fix the loft yourself. First, make sure your attic has sufficient ventilation by checking:

  • Are the ventilation slots unobstructed?
  • Can you spot any storage boxes or possessions that you can remove to enhance airflow?
  • Are there ways you can reduce moisture inside the house?
  • Does your attic require insulation installation?


In case it is the last question, it is time for you to pull out some tools and purchase innovative vents. A lap vent boasts a futuristic design perfect to open the overlapping felt.

Hire an Expert

Secondly, if your roof is in dire need of insulation, you may have to contact a roofing professional. Ensure you do proper background research to check the authenticity and quality of work before working with them.

For our local Connecticut readers, call us for any of your CT Roofing needs. We offer free, no obligation inspections and estimates for any of our services. Our experts will be able to tell you if your attic was properly ventilated and if we see any signs of roof damage to your home. As with most types of roof damage, the more that you wait, the more sever the damage can be. Do not hesitate to call a professional today for a free inspection.