Ice dams cause more winter roof damage in Connecticut than wind does. Here is why they form, what they ruin, and how to stop them before next winter.
If a brown ring shows up on your ceiling a few days after a snowstorm, your roof probably isn't leaking the way you think it is.
Ice dams in Connecticut are the most common cause of that stain, and they have almost nothing to do with the age of your shingles.
Here's what's happening. Heat escaping into your attic melts the snow sitting on the roof above it. That water runs down the slope until it reaches the eave, which hangs past the heated part of the house and stays cold. There it refreezes into a ridge of ice. Every melt after that backs up behind the ridge and sits on the roof, and standing water finds its way under a shingle eventually.
The frustrating part is that this happens to roofs that are only a few years old. Homeowners call about a leak, we inspect, and the shingles are fine. The problem is the attic, not the roof surface. Fixing the ceiling without fixing the cause just means doing it again next February.
An ice dam is a ridge of ice that forms at the edge of a roof and stops meltwater from draining. It builds where the roof gets cold, which is the overhang past your exterior wall. Above that line, warm air in the attic keeps the roof deck above freezing, so the snowpack melts from underneath even when it's below freezing outside.
That meltwater travels down and hits the cold section. It refreezes and the ridge grows a little with every cycle. Behind it, water pools. Shingles are designed to shed water flowing downhill, not to hold standing water in place. Once it's sitting there, it works into the seams and reaches the decking underneath.
If your roof deck stayed the same temperature as the outside air, ice dams wouldn't form. Two things break that.
The first is air leakage. Gaps around recessed lights, bath fans, attic hatches and plumbing chases let heated air from the house into the attic. That air pools at the top of the roof and warms the deck from below.
The second is ventilation. A properly vented attic pulls cold air in at the soffit and pushes warm air out at the ridge. If the intake is blocked by insulation, or there's exhaust with no intake, the air stalls. Blown-in insulation packed into the eaves is one of the most common causes we find, and it usually got there during an energy upgrade that was meant to help.
The ceiling stain is the cheapest part. Water backing up under shingles soaks the roof decking, and wet plywood stays wet through a Connecticut winter because it never gets a chance to dry. Do that for a few seasons and you're replacing sheathing during your next roof job.
It also runs down into the wall cavity. Insulation loses its value once it's wet, and it doesn't recover. Drywall softens. Paint bubbles near the top of an exterior wall. Mold follows in the spots you can't see.
Outside, the weight of the ice pulls at your gutters. Hangers loosen, the run sags, and the fascia board behind it takes water it was never meant to hold.
Start with an inspection that includes the attic, not just the roof. Daylight around a chimney chase, damp insulation, frost on the underside of the deck in January, these all point to the same problem.
Sealing air leaks between the house and the attic comes first. That's where the heat is coming from. Then check that soffit intake isn't blocked and that ridge exhaust is actually moving air.
On the roof side, ice and water shield along the eaves and up the valleys is the physical backstop. It's a membrane that seals around fasteners, so water sitting on it has nowhere to go. Any roof installed in Connecticut should have it. If yours is older, a full roof replacement is when it gets added.
Do not chip ice off with a hammer. Roofs are dangerous in winter and impact damages shingles. Clear gutters going into December — a blocked run holds water right where the ice starts.
Water showing up after a snowstorm won't fix itself. We inspect the roof and the attic, then send a written estimate with the full scope included.
