Ice Dam
An ice dam is a ridge of ice that forms at the edge of a roof when heat escaping through the attic melts snow on the upper roof, the meltwater flows down toward the cold eave overhang, and refreezes against the cold roofline. As more water flows down and freezes behind the dam, the pool of water behind the ice ridge backs up under the shingles, seeps through the roof deck, and enters the attic and wall cavities below. Water damage from a single significant ice dam event can reach thousands of dollars in insulation replacement, drywall repair, and mold remediation.
In depth
In Madison, ice dams form most commonly after snowfall followed by a cold snap below 15°F, particularly on homes with inadequate attic insulation or air-sealing. They are most visible as large icicles hanging from gutters. The correct removal method is steam — low-pressure steamers melt channels through the ice dam without touching the shingles. Hammers, chisels, calcium chloride, and heat tape are poor substitutes that either damage the shingles, only treat symptoms, or create new leak paths.
How this shows up on our jobs
We steam-remove ice dams on Madison homes during winter cold events. Steam is the only method that won't destroy the shingles in the process. We keep a short-notice response list for customers who've had ice-dam damage before.
Services where this matters
Related terms
Gutter Apron
A gutter apron is a flat metal flashing — typically galvanized steel or aluminum — installed under the first course of shingles at the roof edge and bent down into the back of the gutter. It creates a continuous, watertight transition from the roof deck to the gutter trough, preventing water from running behind the gutter and down the fascia board where it causes rot. Without a gutter apron, the slight gap between the shingle edge and the gutter lip allows wind-driven rain and ice melt to work behind the gutter and saturate the fascia.
Drip Edge
Drip edge is an L-shaped or J-shaped metal flashing installed along the eaves and rakes of a roof to direct water off the roof edge cleanly and away from the fascia board and underlying structural components. At the eave, it sits under the first course of shingles and over the top of the gutter, channeling water directly into the gutter rather than letting it wick back under the shingle onto the roof deck. At the rake (the sloping edge of a gabled roof), it sits over the underlayment and under the shingles to shed water sideways off the edge.
Fascia Board
The fascia board is the horizontal board running along the lower edge of the roof, to which gutters are typically fastened. It covers the ends of the roof rafters and gives the roofline a finished appearance. In wood construction, fascia is typically 1x6 or 1x8 pressure-treated or painted pine; in newer construction, it is often PVC or fiber cement. Because it is exposed to constant moisture from gutters, drip, and snow melt, the fascia is one of the most rot-prone boards on a home.
Soft Wash
Soft washing is a low-pressure exterior cleaning method that uses biodegradable detergents and a controlled bleach solution to kill the algae, mold, mildew, and bacteria that cause staining — rather than scouring them off with brute force. A soft wash rig delivers cleaning fluid at roughly 60-200 PSI, comparable to a strong garden hose, which is safe on siding, shingles, painted surfaces, screens, and caulking. The chemistry does the work: the solution dwells on the surface, breaks down the organic growth at the cell level, and is then rinsed clean with fresh water.