Ice Dams: Why Ohio Roofs Leak in January and Stop in March
The icicles look picturesque. The ridge of ice behind them is holding a pool of standing water against a roof that was never designed to be underwater.
How an Ice Dam Forms
Snow sits on the roof. Heat escaping from the house warms the deck in the middle of the slope, and the snow directly above it melts. That meltwater runs down under the remaining snow until it reaches the eave — which overhangs open air and is therefore at outside temperature — and refreezes there.
Repeat that over several days and the frozen ridge at the eave grows. Eventually it is tall enough to hold a pool of standing water behind it. Roofing sheds running water; it is not waterproof against a static pool, so the water works back up under the shingle courses and into the house.
Three Layers of Defence, in Order
1. Stop the heat getting into the attic
This is the actual fix, and it is done at the ceiling plane rather than on the roof. Air leaks are the main culprit: recessed light housings, bath fan penetrations, the tops of interior walls, plumbing and wiring chases, and the attic hatch. Sealing those is more effective than adding insulation on top of leaks.
Then insulation depth, evenly distributed, without blocking the soffit airway. And bath and kitchen fans must discharge outside — a fan dumping warm humid air into the attic is both a heat source and a moisture source.
2. Ventilate so the deck stays cold
Balanced soffit intake and ridge exhaust keeps the deck near outside temperature, so what snow does melt is melting from sunlight rather than from your heating bill. Ventilation without air sealing is treating a symptom, which is why the order matters.
3. Make the eave waterproof anyway
Ohio's residential code requires an ice barrier for asphalt shingle roofs in areas designated as having a history of ice forming along the eaves — either two cemented layers of underlayment or a self-adhering polymer-modified bitumen membrane, running from the lowest edge of the roof to a point not less than 24 inches inside the exterior wall line, measured along the slope. Steeper roofs require it to extend further.
That membrane seals around fasteners and is what keeps standing water at the eave out of the house. On roofs with wide overhangs, deep valleys, or a history of damming, extending it beyond the minimum is money well spent. Requirements and local amendments vary, so confirm with your building department.
If You Have One This Winter
Do not get on the roof, and do not chip at the ice. Hacking at a dam with a hammer or an axe breaks shingles and gouges the deck, and you will be paying for a roof repair in spring on top of the water damage. Do not use salt in a sock either — chloride corrodes metal flashing, gutters, and fasteners, and it kills whatever it drips onto below.
A roof rake used from the ground to pull snow off the lower few feet of the slope removes the fuel and is the safest thing a homeowner can do. Beyond that, steam removal by a company equipped for it is the method that clears a dam without damaging the roof. Inside, contain the water, pull back wet insulation so it can dry, and photograph everything.
Why Central Ohio Gets These
Our winters sit in the awkward band. Consistently very cold climates get less damming because snow does not melt much between storms; consistently mild ones do not accumulate enough snow to matter. Central and northeast Ohio cycle repeatedly across freezing, which is exactly the pattern that builds dams.
Older housing stock compounds it. Homes built before ice barrier requirements became standard frequently have nothing at the eaves beyond ordinary underlayment, and many have had insulation added over the years without anyone addressing air leakage or the soffit airway.
The good news is that the fix is durable. Air sealing, ventilation, and a proper ice barrier at the next replacement generally ends the problem for the life of the roof rather than managing it every winter.
If water is coming in now, call (877) 521-7171 and we will get out to you.
Not Sure Where Your Claim Stands?
We inspect the roof, document what is actually there, and tell you honestly whether you have a claim worth filing.
Common Questions
Primarily they are a heat loss problem. The roof is where the damage shows up, but the cause is warm air escaping into the attic and melting snow from below.
They can manage a persistent problem area and keep a drainage channel open, but they treat the symptom, cost energy to run, and do not address the heat loss creating the dam.
No. Chipping at a dam damages shingles, flashing, and the deck. A roof rake used from the ground on the lower slope is the safe homeowner option; steam removal is the safe professional one.
Chloride products corrode gutters, flashing, and fasteners, and damage plants and masonry below. They are not a good solution.
Roofs installed under current requirements should. Older roofs frequently do not. It is not visible once the roof is on, but it can be confirmed at the next replacement or from installation records.
Related Pages
Book Your Free Inspection
No cost, no obligation, no pressure. Or call (877) 521-7171 — we answer.
No comment yet, add your voice below!