Ice Dams and Roof Damage in St. Louis, at a glance
An ice dam is a heat problem wearing a weather costume: warm air escaping into the attic melts snow high on the roof, and the melt refreezes at the cold eave. Fix the heat loss and the ventilation and the dam stops forming. Call (314) 429-6000 for a free look.
How a dam builds on a St. Louis roof
Snow lands on the roof. Heat leaking from the living space warms the deck under it, and the snow at the top of the slope melts even though the air outside is well below freezing. That water runs down to the eave, which hangs past the heated part of the house and stays cold, and it refreezes there.
Each cycle adds to the ridge of ice at the edge. Eventually the water behind the dam has nowhere to go but sideways and upward, under the shingle courses, through the nail holes and onto the decking. Shingles shed water running downhill. They were never built to hold back a standing pool.
What we do about ice dams
The permanent fixes, in the order they usually matter.
Attic ventilation correction
Intake at the soffit and exhaust at the ridge, balanced so the deck stays near outside temperature.
Ice-and-water membrane
Self-sealing membrane at the eaves and valleys during replacement, so backed-up water cannot reach the deck.
Leak repair after a dam
Tracing and repairing the entry point once the ice is gone and the roof can be worked safely.
Gutter repair and replacement
Gutters pulled loose by ice weight rehung or replaced with hidden hangers.
Winter maintenance
Pre-season checks on flashing, boots and gutters before the first freeze.
Roof replacement
When repeated dams have already soaked the decking, the full rebuild done correctly.
What to do when a dam is already there
Do not chip at it
A hammer or a shovel on an ice dam breaks shingles and lets in more water than the dam did.
Do not put a torch near it
This happens every winter in this metro and it starts house fires. Nothing about an ice dam is worth that.
Control the water inside
Catch what is coming in, move belongings, and photograph the damage for your insurer before cleanup.
Call us
We will steam or safely clear where it makes sense, stop the leak, and then talk about why it formed at all.
Ice dams at a glance
| Cause | Heat escaping into the attic, melting snow that refreezes at a cold eave |
|---|---|
| Where damage shows | Ceilings near exterior walls, attic decking, insulation, gutters and fascia |
| Fastest real fix | Air sealing and attic insulation, paired with balanced ventilation |
| Roof-side protection | Ice-and-water membrane at eaves and valleys during replacement |
| Never do this | Chip at the ice or apply an open flame |
| Roofing company | John Beal Roofing, family owned since 1947 |
Why insulation is a roofing conversation
The answer to a roof leak is sometimes attic work.
Every gap where warm air escapes into the attic contributes: can lights, bath fans venting into the attic instead of outside, an open chase around a flue, a hatch with no weatherstripping. Sealing those and bringing the insulation up to depth keeps heat in the house and keeps the roof deck cold enough that snow stays snow.
Ventilation finishes the job. Intake at the soffit and exhaust at the ridge pulls outside air across the underside of the deck. Older St. Louis houses often have exhaust with no intake, which does nothing in winter and cooks the shingle all summer. We correct it during a replacement.
Signs you had an ice dam, even after the thaw
The evidence stays behind long after the ice is gone.
- Brown staining on ceilings or on the wall just inside an exterior eave
- Gutters pulled away from the fascia, or fascia boards that have gone soft
- Peeling paint or damp insulation in the attic along the outside walls
- Shingle courses at the eave that look lifted or no longer lie flat
- Icicles that formed in a long, heavy row rather than in a few places
- A cold upstairs room that never quite keeps up with the thermostat
St. Louis ice dam questions
Do heat cables solve ice dams?
They can keep a channel open, and they treat the symptom rather than the cause. We would rather correct the ventilation and the attic air leaks so the dam stops forming.
Is ice dam damage covered by insurance?
Often it is, depending on the policy and whether the damage is sudden. Photograph everything before you clean up and talk to your carrier.
Can gutters cause ice dams?
No. Clogged gutters make the ice worse by holding water at the eave, but the dam forms because of heat loss, not because of the gutters.
Should I rake snow off the roof?
A roof rake used from the ground on the first few feet of eave can help. Nobody should be on a ladder in those conditions.
Will a new roof stop ice dams?
A new roof with ice-and-water membrane protects the deck from the water, and corrected ventilation keeps the dam from forming. Both are part of how we install.
Free winter roof inspection
Send this and we will call you to arrange a look at the roof and the attic. If water is coming in now, phone instead.
More winter roofing help
Related pages from our crews:
Ice Damage On Your Roof?
We will look at the roof and the attic together, because one is usually causing the other. The inspection is free.