When to Roof Rake Snow in Chicago, and When to Call a Roofer

You do not have a rule to follow, and we will not invent one. We have no verified Chicago source that gives a snow depth at which a roof must be cleared, so we will not give you a number. What follows is what owners actually see and who to call. Chicago averages 38.4 inches of snow a year, with January and February the heaviest months (NWS Chicago). That is a lot of weight and a lot of meltwater.

Does a Chicago roof need raking after snow?

Most of the time, the question is not "how much snow" but "where does the melt go." Our honest answer: it depends on the roof, and a roofer who has seen it should decide. We have not verified any City of Chicago rule that makes roof snow removal an owner duty, so check with the Department of Buildings if a notice or insurer asks.

Flat roofs are the common Chicago case. Snow melts, and the water has to reach a drain or scupper. If drains are blocked by leaves and debris, water backs up and sits. The Asphalt Roofing Manufacturers Association defines ponding as water that stays on a low-slope roof 48 hours or longer, and says it can overload the deck, clog drains, wet insulation and wear the membrane faster (ARMA). A secondary overflow drain may be required by local plumbing code (ARMA). Clearing the drain area before a thaw is usually the helpful chore, and a roofer can tell you if it is safe to do. See our post on flat roof snow load and ponding on a flat roof.

Pitched and shingle roofs (many bungalows, for example) shed snow differently. Ice at the eaves, icicles, and water stains on upstairs ceilings or at the wall below the roofline are what owners see when melt and refreeze are fighting the roof. The causes are a roofer's diagnosis. We have not verified a specific ice dam rule, so we will not state one. Our ice dam post covers what is known.

What are the warning signs to act on?

Call a roofer or, for structural worry, an engineer, if you see:

• A ceiling that sags or a new stain that grows after each thaw.
• Doors or windows that suddenly stick in winter.
• New cracks in plaster or at the corners of ceilings.
• Water standing on a flat roof for a day or more after the melt.
• A sagging roofline, or ice forming heavy at the eaves or on the gutters.

Should you go up there yourself?

No. Snow hides edges, drains and soft spots, and ice makes a roof slick. Do not climb onto a snowy roof, and do not hack at ice, which can tear membrane or shingles. From the ground, look at the roofline and photograph anything odd. If you want snow cleared, hire someone who does roofs for a living. If the roof leaks after the thaw, read where Chicago thaw leaks come from.

One permit note. A roof repair limited to 25 percent of the roof area, with no part of the roof or exterior wall cut away, is exempt from a building permit under the City's list; re-roofing and structural repairs are different, so confirm with the Department of Buildings (City of Chicago). Our roofers can look at it, and the seasonal calendar shows when to check.

Common questions

This article explains general rules and common situations in Chicago. It is not legal advice, and City rules change. For a specific property, check with the Chicago Department of Buildings or a licensed professional.