Ice Dams and the Damage They Leave
An ice dam is the roof telling you about the attic. The ice sits at the eave, but the cause is warm air leaking up from the rooms below.
How a dam forms
Heat escapes into the attic or the roof deck, the snow on the upper roof melts from underneath, and the water runs down until it reaches the eave, which hangs out past the heated wall and stays cold. It freezes there. Each day the ridge of ice gets taller and the water behind it pools, until it backs up under the shingles, which are built to shed water, not hold it. Minnesota's Center for Energy and Environment puts it simply: in most cases the problem starts inside the house.
Why Minneapolis houses get them so badly
Story-and-a-half houses are the classic case. The upstairs rooms sit partly inside the roof, with sloped ceilings and short knee walls, and there is very little space between the plaster and the roof deck for insulation. The knee-wall attics behind the closets are often leaky and under-insulated. Heat gets to the roof deck easily, right above the coldest part of the eave.
Longfellow, Nokomis, much of Southwest and plenty of Northeast are full of these houses, built from the 1910s through the 1940s. Researchers in a federal Building America study chose Minneapolis story-and-a-half houses precisely because they are common here and hard to air seal.
Getting the ice off safely
A roof rake from the ground, pulling the bottom few feet of snow off after each storm, reduces the meltwater feeding the dam. Rake gently; aggressive raking damages shingles.
Do not climb up and chip at the ice. Hatchets, hammers and shovels break shingles, and the roof is at its most slippery. Heat cables are a poor long-term answer: they cost money to run and wear the roof around them.
For a dam that is already leaking, roofing and ice-removal companies use low-pressure steam to cut channels through the ice without damaging shingles. It is usually billed by the hour, and in a bad week every company in the metro is booked.
The damage to look for in spring
Once the snow is gone, look at the bottom three or four feet of the roof from the ground and the attic: stained or soft decking at the eaves, rusted nails, peeling paint and swollen trim on the soffit, gutters pulled away from the fascia by the weight of ice, and water stains on the interior walls below. Damage at the eave is where a repair can turn into new decking, and that is worth knowing before the next winter, not during it.
Had an ice dam this winter? Book a spring look now, while the damage is fresh and before the roofing calendar fills.
The fix that lasts
Air sealing and insulating the attic is the long-term answer, and Minnesota utilities support it. CenterPoint Energy and Xcel Energy both run attic air sealing and insulation rebates, and the Home Energy Squad program offers a low-cost home visit to find the leaks first. Rebate amounts and rules change, so check with your utility before you hire. On a reroof, the ice barrier at the eaves is the second line of defence. It does not stop a dam forming; it limits what the water can do when one does.
Common questions
Should I hire someone to remove an ice dam?
If water is coming in, yes, and ask for steam rather than chipping. If there is no leak, raking the lower roof and planning the attic work may be enough.
Will a new roof stop ice dams?
Not on its own. A new roof with proper ice barrier limits the damage, but the dam forms for the same reason as before unless the attic heat loss is fixed.
Does homeowners insurance cover ice dam damage?
Many policies cover sudden water damage from an ice dam and exclude wear, but policies differ. Ask your insurer before work starts.
Other roof work in Minneapolis
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Also serving
Ice Dams is available beyond Minneapolis, across Southwest Minneapolis , Northeast Minneapolis , Edina , St. Louis Park and Richfield .
Ask about ice dams
Say what you are seeing: a stain, ice at the eaves, shingles in the yard. A local roofing company will reply and arrange a look, usually within a few days, sooner for an active leak. Answered Mon–Sat · leave a message after hours and you get a call back Or call (651) 381-5283 if it is leaking now; a person picks up faster than a form gets read.