Ice Buildup on Your Roof Causing Leaks? NJ Ice Dam Help

Why ice dams form: it starts in the attic

An ice dam isn't really a roof failure. It's a heat problem that shows up on the roof:

1. Warm air leaks into the attic from the house — around light fixtures, attic hatches, plumbing and wiring holes, and through thin insulation.
2. The roof deck warms up over the living space, and the snow on top of it melts even when it's below freezing outside.
3. The water runs down to the eaves, which hang out past the warm walls and stay cold. There it refreezes.
4. The ice ridge grows with every melt-and-freeze cycle, and the meltwater behind it pools on the roof.
5. Water backs up under the shingles. Shingles shed water running downhill; they aren't built to hold back a pond. It finds the nail holes and seams and gets into the wall and ceiling.

Poor ventilation makes it worse: without cold air moving under the roof deck, the attic stays warm. Clogged gutters add to the ice at the edge, but they don't cause ice dams on their own. More: ice dams from poor ventilation and improper attic airflow.

What not to do about ice dams

When water is dripping into the house, it's tempting to go after the ice. Some of the most common ideas do more harm than good:

• Don't chip the ice with a hammer, axe or ice pick. It's easy to cut or crack shingles and gutters, and it's dangerous on a ladder.
• Don't climb onto the roof. Snow over ice is extremely slippery, and falls from roofs in winter cause serious injuries.
• Don't use rock salt on the roof. It can damage shingles, metal flashing, gutters and the plants below.
• Don't pressure-wash or use open flame. High pressure forces water under shingles, and heat guns or torches are a fire risk.
• Don't caulk the leak from inside. The water is coming from the roof; sealing the ceiling just hides where it goes.

Permanent solutions for ice dams on roofs

The real solution for ice dams is to keep the whole roof deck cold and give the eaves a backup layer of protection. That means work in the attic and on the roof:

1. Seal and insulate the attic floor

Stopping warm air from leaking into the attic is the single biggest step. Air sealing around penetrations and topping up insulation keeps the heat in the living space instead of on the roof. See attic insulation top-up.

2. Balance attic ventilation

Cold outside air should come in at the soffits and leave at the ridge or through roof vents, keeping the underside of the roof close to outdoor temperature. Blocked soffit vents are common. Solar attic fans can help on some roofs. See attic ventilation and blocked soffit vents.

3. Install ice & water barrier

A self-sealing membrane under the shingles at the eaves, in valleys and around penetrations. It doesn't stop ice dams from forming, but it stops the backed-up water from getting into the house. It's installed when the roof is replaced. See ice and water shield.

4. Fix gutters and downspouts

Gutters that are sagging, clogged or pitched the wrong way hold water and ice at the edge. See gutter ice dam prevention.

After the thaw: checking for ice dam damage

Ice dam leaks often keep causing damage after the ice is gone. Once the weather breaks, check:

• Attic insulation — wet insulation loses its value and can hold moisture against the ceiling.
• Ceilings and walls — stains, soft drywall, peeling paint and swollen trim near outside walls.
• Roof decking at the eaves — repeated leaks can rot the wood. See ice dam roof damage.
• Gutters and fascia — ice weight can bend gutters and pull them off the fascia.
• Mold — any area that stayed wet for days. See mold from a roof leak.

Some homeowners policies cover sudden water damage from ice dams; coverage depends on your policy and the insurer decides. We can document the damage with photos and measurements and help with paperwork. If the roof is near the end of its life, see roof replacement after ice dam damage.