If you've lived through a Merrimack Valley winter, you've seen them: thick ridges of ice building up along the eaves, icicles hanging off the gutters, and — in the worst cases — water stains spreading across ceilings and down interior walls. Ice dams are one of the most common and most expensive winter problems we see across Lowell, Nashua, and southern New Hampshire.
Ice dams form when heat escaping from your living space warms the roof deck and melts the snow sitting on it. That meltwater runs down the roof until it hits the cold overhang at the eaves, where it refreezes. Layer by layer, an ice ridge builds up — and the water pooling behind it has nowhere to go except under your shingles and into the house.
The real fix isn't roof raking or heat cables (though both can help in a pinch). It's building the roof system right: air-sealing and insulating the attic floor so heat stays in the house, ventilating the attic so the roof deck stays cold, and installing ice and water shield membrane at the eaves and valleys so any water that does back up can't reach the wood below.
If you're seeing recurring ice dams, water stains after cold snaps, or icicles thicker than your arm, have the roof and attic evaluated before next winter. Pro Home Exterior Corp offers free inspections and estimates across NH and MA — we'll tell you honestly whether you need better ventilation, targeted repairs, or a full roofing system built for New England winters. Call (603) 479-4831 to schedule.