Ice Dam Roof Leak: What to Do When Water Comes Through the Ceiling

Warm air from the living space leaks into the attic and heats the underside of the roof deck. Snow on the upper roof melts, the water runs down to the overhang, which stays as cold as the outdoor air, and it freezes again. Day after day the ridge of ice grows until it holds back a pool of water that works its way under the shingles. The U.S. Department of Energy's Building America Solution Center notes that an ice dam can form with as little as 2 inches of snow on a roof.

Indiana County and Westmoreland County get plenty of the snow and the freeze-thaw swings that feed this cycle. NOAA's 1991-2020 climate normals for the Indiana 3 SE weather station show close to 46 inches of snow a season and about 131 nights a year at or below freezing. A sunny January afternoon followed by a hard overnight freeze is exactly the pattern that builds ice at the eaves.

Older houses are more exposed. Census estimates put the median home in Indiana Borough at 1957, decades before modern energy codes, and many homes in Blairsville, Greensburg and Latrobe are of a similar age. Attic heat leaks commonly escape around chimneys and flues, recessed lights, attic hatches, plumbing vents, bath fans and knee walls in finished upstairs rooms.

An ice dam leak usually shows up on the top floor or in a finished attic room, along an exterior wall or near a corner of the roof. It tends to appear after snow, often on a milder or sunny day when melting speeds up, and it may slow down overnight when everything freezes again. Outside you will often see a thick band of ice along the gutter line and heavy icicles.

A plumbing leak behaves differently. It usually sits below a bathroom, kitchen or water line, and it keeps going regardless of the weather. If water continues while every fixture is off, or the leak is on a lower floor, read our emergency plumbing guide and treat it as a possible burst pipe instead.

Move people and pets out of the room if the ceiling is sagging, bubbling or cracking. A drywall ceiling holding water can come down without much warning. Do not stand under it to poke it or push it back up; a provider can drain it in a controlled way.

If water is near a light fixture, ceiling fan, outlet or the electrical panel, keep away. Switch off the affected circuit only if you can reach the breaker panel while standing on a dry floor. If anything sparks, smokes or smells hot, leave the area and call 911.

Then limit the damage. Put buckets or a tarp under the drip, move furniture and electronics away, and lift rugs. Take dated photos and short videos of the ceiling, the wet areas and the ice on the roof edge from the ground. Those images help your insurance claim and help a provider plan the visit before they arrive.

Taking snow off the roof removes one ingredient an ice dam needs. The National Weather Service and the Insurance Institute for Business & Home Safety both point to a long-handled roof rake used from the ground. A rake with wheels helps keep the blade off the shingles. Watch your footing, and stay well clear of the line where power enters the house.

When water is actively entering the house, University of Minnesota Extension describes cutting a drainage channel through the dam with tap water from a hose on a warm day, working upward from the lower edge. It warns that the channel only lasts a few days and is a temporary measure.

Avoid the tempting shortcuts. Minnesota's energy office advises against chipping ice, using chemicals or applying heat, because they can damage shingles and gutters. Do not climb a ladder onto an icy roof edge. If the dam is large or the leak is getting worse, a professional crew can remove the ice safely, often with steam equipment.

Stopping the drip is only half the job. Wet drywall, ceiling insulation and the wood framing above can hold water long after the ceiling looks dry. The EPA's guide to mold and moisture recommends drying water-damaged areas and items within 24 to 48 hours to help prevent mold growth.

A water damage restoration provider can check moisture levels in the ceiling and attic, set up drying equipment and tell you which materials can be dried and which need replacing. Soaked attic insulation often loses much of its value and may need to come out. Ask for a written scope that separates the drying work from any rebuilding.

The Building America Solution Center lists three ways to prevent ice dams: air seal the ceiling between the house and the attic, insulate the attic thoroughly, and ventilate the roof. Air sealing comes first, because it stops the warm air that melts the snow. Baffles at the eaves keep insulation from blocking the soffit vents so cold air can move along the underside of the roof.

The National Weather Service page on roof ice dams says most experts agree attic insulation should be at least R-30, with R-38 preferable in northern climates, and recommends keeping gutters and downspouts clear before winter. When a roof is replaced, the Department of Energy describes sealing the eaves with a self-adhering waterproof membrane as an added layer against water backing up under shingles.

Heat cables get mixed reviews. The Insurance Institute for Business & Home Safety says professionally installed, listed cables can keep drainage channels open but will not remove an ice dam, while Minnesota's energy office recommends against them. Ask the roofer or insulation contractor what is causing the heat loss before paying for any one product.