With the New Year’s festivities behind us, it’s time to focus on keeping your home warm and cozy for the winter. We want to help broaden your knowledge of how to effectively Winterize Your Home and this blog focuses on Preventing Ice Dams on your roof.

Remember those 5’ long icicles hanging off of the side of your house last winter? Or the large snow glare that was 5” thick? Yep, those are sure signs of Ice Dams.

If you have ever suffered through an ice dam, it’s a pretty horrific situation. It usually occurs in the dead of winter as snow piles up on your lawn and your roof and temperatures plummet to unbearably freezing degrees. The likely result of an ice dam on your roof is water trickling in through your walls, across your ceiling and into your light fixtures. It’s a homeowner’s worst nightmare and something that you definitely want to prevent from occurring.

prevent ice damsAn Ice Dam is formed by a build-up of ice at the edge of your roof. When your attic is too warm,  the snow and ice closest to the shingles starts to melt resulting in streams of water coming down past the warm parts of your attic and soffit (the overhang of your roof) where there is no heat. Slowly these drops of water start to freeze up and build up an edge. The water continues to flow and it becomes blocked by the newly formed ice dam. As more water freezes, it begins to back up under the shingle tabs and into your home. You may see 4-5” of glare ice and icicles. This is when you should say to yourself, Should I really have this much water melt off? The answer is no. It means that you have too much water coming off your roof because your attic is too warm.

Causes of a warm attic:

  1. You don’t have enough insulation in your attic.
  2. Bathroom vent fans are not insulated or closed off which results in warm heat blowing into the attic.
  3. Open plastic vent tubes are also warming up attic!
  4. Recessed light receptacles are not always installed right and if they are not insulated properly heat can pour through them.

Bottom line, a warm attic is not a good thing.

So what can you do?

You need to make sure you have enough ventilation in your attic. It doesn’t matter how much insulation you put up there, if you don’t have enough venting you will have a risk of ice dams as you need to move air through. In a perfect world, your attic should be the same temperature as outside. You should have 1” sq. ventilation per sq. foot of attic space. Do you have this? If not, you’re not only in danger of ice dams and extra money on your energy bills, you can also have mold problems. Air travels everywhere-basement, outlets, seams, plumbing breaches, door sills-everywhere! You need to make sure your roof is properly insulated and ventilated. I call this the I-V Quiz! Let’s see how you do…


When you’re up in your attic putting away your holiday decorations, check out your attic for:

  1. Is the temperature the same as outside?
  2. Do you see any condensation on items?
  3. Do you see uninsulated recessed lighting cans or bathroom vent pipes?

What To Do:

  1. Most importantly caulk and seal the sill plate that rests on the foundation in your basement with caulk/foam as the air starts to chimney. Avoid this “chimney effect” as it travels up your house to your attic.
  2. Seal up your attic and insulation to at least R-38.
  3. 3. Have us check your attic ventilation to ensure proper air movement, roof barriers to prevent roof leaks, and gutters making sure they channel the water away from your home.
  4. 4. Foam around your heat protected lights (make sure they are fire rated/0-Clearance)
  5. 5. Seal up attic hatch
  6. Proper insulation and ventilation are the keys to preventing Ice Dams. Mold and Moisture problems usually are a result of improper insulation and ventilation and they don’t go away- they get worse. If you see any of these issues, call us today before the snow comes. We hope you found these tips on how to prevent ice dams helpful. Please contact us today if you need more information on ice dam prevention.

    Coastal Windows & Exteriors also offers snow raking and attic and roof inspection services if you need them this winter. Coastal Windows & Exteriors provides free estimates on roofing, siding, windows and doors and services all of Massachusetts, New Hampshire, and Rhode Island.