Roofing in St. Louis is wind and hard rain more than hail. Ridges lift, valleys run, and brick parapets send water sideways into a top-floor ceiling. Flat and low slopes behind those walls pond and open a seam. Steeper asphalt on a house roof fails at the chimney and the boots. Clay tile and slate still exist on older buildings and should be named, because they are not a shingle patch. Look from the alley as well as the street.
A stain that grows during a river storm and pauses when the sky clears is the roof or the coping talking. A stain that continues after the rain, with a gurgle in the basement, may be the drain instead. Say which. Blown-off edge metal and missing tabs are wind. Ponding means the drain, the scupper, or the slope quit. Ice can still form in a hard winter and should not be the default story in August.
Counterflashing into brick, coping joints, and pitch pans decide whether the repair lasts. Soft deck under a pond is structure. Wet insulation changes the weight. Temporary cover matters when another line of storms is west of the rivers. Keep people off a wet membrane or a slick slate. Debris has to leave a tight lot. Do not describe a pitched bungalow roof as if it were a downtown flat roof.
Scope includes the metal edge, the way the parapet is tied in, and the boots, not only the field that looks obvious. A party wall can make a leak feel like the neighbor's until you are under it. Skylights and old hatches are punctures. If two units share the roof, say so before anyone strips one side. Ventilation still matters on the steep roofs that do ice. Say the system you have.
Say flat roof or steep, leak or blow-off, and which floor is stained. St. Louis wind will test the coping you leave open. Call the number on this page.