Chicago stands up in brick, stone, and lake wind. Bungalows, greystones, two-flats, and courtyard buildings take weather on masonry, not on a wide open field. An east wind off the lake drives rain sideways into parapets, copings, and worn limestone sills. A west wind in January finds every open mortar joint and every loose storm window. The building is older than the last blow, and the call starts with what it is made of.
Tuckpointing is not decoration here. When the joint is gone, lake-driven water sits in the wythe and then freezes, and the brick face lets go. Parapet walls crack at the corners. Chimney crowns crumble and dump grit into the gutter. Flat roofs behind those parapets pond, then find a seam. A bungalow with a steep asphalt roof a few blocks away is a different building and a different failure, even on the same street.
Basements sit in clay, and the alley hides the lateral, the catch basin, and the downspout. Gangways are tight, which matters when a condenser, a meter, or a person has to fit. Winters are radiators in much of the older stock and forced air in bungalows changed later. Summers are humid enough to show every flat-roof leak as a ceiling ring. Wind off the lake makes a small gap into a whistle.
Say whether it is a bungalow, a greystone, a two-flat, or a courtyard building. Say which floor has the symptom. Water at a top-floor ceiling is often the roof or the parapet. Water at a garden-level floor is often grade, a window well, or the drain. Heat that fails in a radiator building is not the same sentence as a dead condenser in a gangway.
Chicago will keep throwing lake wind and hard freezes at mortar, roofs, and old sash. Name the side of the building that faces the lake if that is the wet wall. Pick the trade that matches the material in front of you, and say what the last blow did. Pick the trade and call.