Why Does My Attic Have Condensation?
- Attic condensation generally happens during winter & spring months when warm, moist air from the main living area rises into the attic space. When that warm, moist air meets the chilly underside of your roof’s deck, condensation occurs. This can also be greatly exacerbated if there are swings in the climate going from heavy warm weather rains to immediate cold weather overnight. The already very humid airmass will take time to dry out, not only outside your home but inside your attic
- In the winter, attic condensation often turns into frost, which doesn’t pose any threat. However, when the frost melts, it turns back into condensation, which makes everything it touches wet – usually insulation and wood.
- Throughout winter, your home should have about a 35% to 40% humidity level. If your humidity levels are higher, condensation can occur inside the home and can be witnessed on windows, walls, and ceilings. And depending on the home, even 35% can be too much.
- Some common sources for attic moisture are showers, dishwashers, dryers, cooking, washing machines, baths, humidifiers, and other heat-producing machines. Homes with a lot of people living in the area and even plants will add to this as well. In most cases, these sources do not produce excessive moisture, however, if a house is very airtight and/or if ventilation is poor – it can certainly contribute greatly.
What Causes Attic Condensation?
- Poor attic insulation and/or ventilation
- Improperly vented bathroom and dryer exhausts that are routed to the attic (instead of outside)
- Should the connection of a bathroom vent become detached from roof exhaust point. this would significantly contribute to the attic humidity
How Do I Know if I Have Attic Condensation?
There are a few signs you can look for to determine if you have attic condensation:
- Signs water has (or is) trickling down the walls
- Musky, damp odor
- Dark stains
- Damp or wet insulation
- Damp or wet wood
- Water marks on the floor
- Moisture on glass windows
How to Get Rid of Attic Condensation
In order to stop condensation (and frost) from developing in your attic you need to do 4 things:
- Eliminate or reduce air leakage into the attic space
- Depending on which town you live in, Mass Save will Air Seal any penetrations you may have in your ceiling such as Can lights, Bathroom fans, or any other penetrations into the attic space at almost little to no cost.
- Attic Entry: this is the biggest and most common problem we see when inspecting a roof when we look in the attic when the access is not correctly sealed and insulated
- Pull Down Stairs: Need to have an insulated box over the stairs to prevent moisture and heat escaping from the home into the attic. Mass Save Can supply these or you can even buy one at Lowes: Owens Corning Attic Stairway Insulator II 40-in Insulation Supports for roughly $58
- Walk Up Attic: A full sized entry door is installed but not the correct door! The door separating the top floor from the attic space should be an insulated exterior door that is also tightly sealed to prevent heat and moisture from escaping the home into the attic.
- Improve attic insulation
- Most homes do not have sufficient insulation allowing heat to escape through the ceiling and into the attic space. Calling Mass Save can greatly reduce if not eliminate this problem by adding in additional blown in insulation over your existing insulation at almost little to no cost.
- Improve attic ventilation
- If you have vented soffit or drip edge, make sure any fiberglass or blown in insulation is not blocking the air intake as this could greatly reduce the house’s ability to breathe
- Make sure any visible ridge vents are properly cut in and not blocked
- If Gable vents are used rather than ridge vents are there enough exhaust for the house to breathe?
- Ensure bathroom & dryer vents are properly routed outside
- Many homes we have seen vent their bathroom fans into the soffit or even a sidewall.
- If you have vented soffit or drip edge, the Massachusetts Building Code clearly states that you cannot vent anything OUT of your attic space within 3’ of air coming IN to your attic space as the house could pull that moist air back into the attic space.
Did the Installation of My New Roof Cause This Issue?
- Every roofer will get this question in the Fall as things quickly start to get cold and the answer is almost always NO
- If your home was already leaking moisture into your attic space, then the addition of a new roof would not change this. Only if the amount of ventilation into/out of your attic changed, could this exacerbate the issue.
I’ve Never Seen This Issue Before!
- Only now, because you have had a new roof installed, are you more likely to check your attic space for possible leaks and recognize things that were already present in the past yet not seen.
- Rapid changes in temperature and humidity outside the home can drastically change the environment inside the attic, making this visible one day but not the next.
- These issues in the Northeast are most commonly seen after a rapid cold front follows moist heavy rainstorms in which the outside air is already very humid and then turns cold quickly
If you have seen this even once, then you can be certain this has happened before, and your attic moisture issue must be addressed for this to stop!
If you’ve noticed condensation or signs of condensation in your attic, call Beantown Home Improvements right away! We can help you address your concerns and keep your home safe all year long!