Winter in Boise, Meridian and Nampa often brings snow followed by sunny days and cold nights. That pattern is exactly what creates ice dams, one of the most common causes of winter roof leaks we see.
What an ice dam is
An ice dam is a ridge of ice that builds up along the lower edge of your roof. Snow higher on the roof melts, the water runs down, and it refreezes when it reaches the colder eaves. Over time that ridge grows. New meltwater gets trapped behind it, and with nowhere to go, it can back up under your shingles and into your attic, walls or ceilings.
Why they form
The main cause is heat escaping into the attic. When warm air from your living space leaks upward, it warms the roof deck and melts the snow from underneath, even when it is below freezing outside. The eaves stick out past the warm part of the house, so they stay cold and the water refreezes there. Common contributors include:
- Thin or uneven attic insulation
- Air leaks around light fixtures, attic hatches and plumbing or electrical openings
- Poor attic ventilation that traps warm air
- Clogged gutters that hold ice and snow at the roof edge
Warning signs to watch for
- Thick ice along the eaves or in the gutters
- Large icicles hanging from the roof edge
- Water stains or damp spots on ceilings near exterior walls
- Peeling paint or moisture on walls during or after a thaw
- Uneven melting, with bare patches high on the roof while snow stays at the edges
What to do if you have one
Safety comes first. Please do not climb onto an icy roof or chip at ice with a hammer or shovel. That can damage shingles and is a quick way to get hurt. A roof rake used from the ground can pull snow off the lower few feet of the roof and reduce the meltwater feeding the dam. If water is already coming inside, catch it, protect your belongings and give us a call.
How to help prevent ice dams
The lasting fix is keeping your roof deck cold and evenly temperatured.
- Seal air leaks between your living space and the attic.
- Add insulation where it is thin so less heat reaches the roof.
- Make sure your attic has balanced intake and exhaust ventilation.
- Keep gutters and downspouts clear before winter arrives.
When a roof is replaced, a waterproof underlayment along the eaves adds another layer of protection against water that backs up.
Repairing the damage
After the thaw, it is smart to have your roof checked. Ice dams can lift shingles, loosen flashing and bend gutters. We look closely at the edges, valleys and attic, explain what we find in plain language and recommend a repair that fits the problem.
If ice dams have caused trouble at your home, call us at (208) 555-0199 or request a quote. We are glad to help you get ready for next winter.