Ice Dam and Winter Roof Damage Repair

Ice dams are the defining roof problem in Milwaukee, and they are the reason most winter roof leaks here have nothing to do with the shingles. If water is coming into your house in January and February but the roof is fine in a summer downpour, this page is almost certainly describing your problem.

How an Ice Dam Actually Forms

It is a heat problem before it is a water problem, and understanding the sequence tells you why some fixes work and others do not.

• Heat escapes from the living space into the attic — through gaps around light fixtures, bath fans, attic hatches, plumbing chases and the top plates of walls.
• That heat warms the roof deck from underneath, and the snow sitting on the upper roof melts.
• The meltwater runs down toward the eave, which overhangs unheated space and stays at outside temperature.
• At the cold eave it refreezes, and a ridge of ice builds along the edge over successive days.
• Water melting behind that ridge now has nowhere to go. It backs up, finds the seams between shingles, and travels sideways under them.
• Shingles shed water flowing downhill. They are not designed to stop water sitting still and pushing uphill, which is exactly what an ice dam creates.

That last point is the one worth remembering. Nothing about the shingle failed. The roof was asked to do something no shingle roof can do.

What Ice Dam Damage Looks Like

• Ceiling stains near exterior walls, usually in an upstairs bedroom, appearing in a thaw rather than during a storm
• Water running down the inside of an exterior wall, or staining at the top of window trim
• Peeling paint on soffit and fascia, and damp or rotted fascia board
• Damp or compressed attic insulation above the affected wall — insulation that has been wet has lost R-value permanently
• Icicles and a visible ice ridge along the eave. Icicles are pretty and they are a symptom
• Gutters pulling away from the fascia under the weight of trapped ice
• Mold or a musty smell in the attic, which is what repeated winter wetting eventually produces

Some of this shows up months later. Water that got into a wall cavity in February can appear as a stain in April, and by then most homeowners have stopped connecting it to winter.

Why Chipping the Ice Off Is the Wrong Answer

When there is water coming in, the instinct is to get the ice off the roof. Please do not do it with a hammer, a chisel, an ax or a shovel — and be skeptical of anyone who offers to.

Shingles in freezing weather are brittle. Chipping ice off them breaks the shingles, tears the underlayment, and turns a temporary water problem into permanent roof damage that will not be visible until spring. Rock salt and de-icing chemicals sitting on shingles are also destructive, and they corrode gutters, fasteners and anything metal they run over.

Emergency steam removal is the correct method, done by someone who does it properly, and it is a stopgap. Raking snow off the lower few feet of the roof after a heavy fall genuinely helps and is something you can safely do from the ground with a roof rake.

The Real Fix Is Not a Roof

We would rather be direct about this than sell you something that does not solve your problem. A new roof, on its own, often does not stop ice dams. If heat is still escaping into the attic, snow will still melt and refreeze at the eave regardless of how new the shingles are.

What actually stops them, roughly in order of effectiveness:

• Air sealing the attic floor. Closing the gaps that let warm house air into the attic in the first place. This is the root cause and the highest-value work.
• Adequate insulation, so less heat reaches the deck.
• Balanced ventilation. Soffit intake matched to ridge exhaust, so the attic runs at close to outside temperature. Most older Milwaukee homes have exhaust and little or no intake — see why proper roof ventilation matters.
• Ducted bath and kitchen fans terminating outside, not into the attic. We find fans venting into attics constantly, and each one is a heat and moisture source directly under the roof.
• Baffles at the eaves so insulation does not block the intake vents it sits next to.
• An ice barrier membrane at the eaves, which is the roofing part. It does not prevent the dam — it prevents the dam from putting water in your house.

The last one is why a roof replacement matters here even though it is not the whole answer. It is the one moment the deck is open, the intake side can be corrected, and a self-adhered ice-and-water membrane can be run up from the eave past the exterior wall line. Doing it during a replacement costs a fraction of doing it later.

What We Do

• Diagnose the cause, not just the leak. Attic inspection with photographs — where the heat is escaping, whether intake exists, whether the insulation has been wet.
• Repair the damage to decking, fascia, soffit and the roof itself.
• Correct the intake ventilation and install baffles where they are missing.
• Install ice barrier membrane at eaves and valleys on any replacement.
• Document everything for an insurance claim, because sudden interior water damage from an ice dam is often covered even where the roof itself is not. See roof insurance claims.
• Tell you when the answer is an insulation contractor rather than a roofer.

If the roof is at the end of its life anyway, see roof replacement — and financing if the timing is the obstacle. If it is isolated damage, see roofing repair. For summer damage, see wind and storm damage repair.

More about us in southeastern Wisconsin on our Milwaukee roofing page, or check whether you are in our service area. Start with a free roof inspection.

Frequently Asked Questions