Chimney and fireplace service on the North Shore and in Lake County

Along the lakefront the houses are old. The Census Bureau's 2020 to 2024 survey dates 48.8 percent of Winnetka's homes and 40.3 percent of Evanston's to 1939 or earlier; Winnetka's median home was built in 1942 and Evanston's in 1953. Wilmette is a little younger but mostly pre-war and postwar together, with 28.6 percent of its homes from before 1940 and another 27.0 percent from the 1940s and 1950s. Those houses were built with masonry fireplaces and clay-tiled flues, many of which have now stood through 70 to 100 Illinois winters.

Inland and to the north, the picture changes. Across Lake County as a whole only 8.4 percent of homes predate 1940 and the median home dates to 1983, so in much of Libertyville, Mundelein, Vernon Hills and Gurnee the fireplace is factory-built or gas, with a metal flue inside a framed chase. Gas is the main heat almost everywhere: 75.3 percent of homes in Evanston, 87.4 percent in Winnetka and 83.2 percent across Lake County.

Lake-effect snow and the side of the stack that faces the water

On November 9 and 10, 2025, lake-effect bands off Lake Michigan dropped 10.0 inches on Winthrop Harbor, 5.2 inches near Evanston, 5.1 inches near Mundelein and 5.0 inches in Gurnee, while O'Hare recorded 1.7 (NWS Chicago). The Weather Service noted snowfall rates above 2 inches an hour in Lake County and thundersnow near the shore. In the February 2019 storm it again found the highest totals in Lake County and northern Cook, with Northbrook at 6.8 inches before the lake-effect snow had even begun.

Snow banked against a chimney melts on a sunny afternoon, runs into the flashing and the crown, and freezes again overnight. O'Hare, the closest long-term station, sees about 78 days a year that cross the freezing line (derived from NOAA 1991 to 2020 normals). After a heavy lake-effect winter, these are the faults we find most:

• Counter-flashing pulled away from the brick on the lake side; flashing repair typically costs $300 to $1,800
• Crowns that are only a thin sloped mortar wash, cracked through; a new poured crown runs $1,000 to $3,000
• Missing or rusted caps that let snow fall straight down the flue
• Open mortar joints near the top of the stack, where wind-driven snow hits hardest

Old Evanston and Winnetka flues serving gas appliances

In a 1920s house the chimney that once took a coal or wood fire now usually vents a gas boiler or furnace and a water heater. Gas exhaust is mostly water vapor and it cools in a big, cold masonry flue, so the moisture condenses on the tile and soaks into the joints. We check every flue from the top and from the basement. When the tile is cracked or the flue is far too large for the appliance, a liner sized to it fixes both problems: an aluminum liner for gas appliances only typically runs $625 to $2,250 and a stainless steel liner $900 to $3,800.

Chase covers and gas fireplaces farther inland

On a factory-built fireplace the weak point is usually the chase cover, the metal lid on top of the framed chimney. Once it rusts or holds standing water, the water finds its way into the chase and down the walls. A custom chase cover typically costs $425 to $850. Gas fireplaces that won't light or won't stay lit are the other common call; an igniter usually runs $90 to $150 and a thermocouple $150 to $350. Nicor Gas warns that snow covering a gas vent can cause a dangerous carbon monoxide buildup, so after a lake-effect storm clear any side-wall vent by hand or with a broom, not a shovel.