What Should Be on Your Chicago Winter Flat Roof Checklist?

Chicago winters do not break flat roofs at random. They break them at specific, predictable points: the clogged drain that becomes an ice pond, the lifted seam edge that freeze-thaw pries open, the flashing gap that lets meltwater behind the membrane. The good news is that every one of those points can be checked in about an hour, in November, by someone who is not a roofer. This is that checklist. Print it, walk the roof with it, and your building enters winter with its odds dramatically improved. No purchase required; this one is genuinely free value, because a facilities manager who catches problems small is better for everyone, including us.

Before you go up

Pick a dry day above freezing, tell someone you are going up, and use the roof hatch or ladder access rather than anything improvised. Bring your phone for photos, gloves, and a trash bag for debris. Stay off the roof entirely if it is wet, icy, or windy, and stay away from unprotected edges and skylights, which are fall hazards year-round and worse under any frost. If any of that is not workable, do the drain checks from the hatch and leave the walking to us. Nothing on this list is worth a fall.

The checklist

1. Drains, scuppers, and gutters: the whole ballgame. Walk to every roof drain and pull the debris off the strainer: leaves, litter, tennis balls, the works. Check that strainers are actually in place and intact, then check scuppers and overflows for blockage. Here is why this is item one: a drain that is 80 percent clogged in November is 100 percent clogged after the first freeze, and a blocked drain in January means standing water becoming standing ice, adding real structural load and grinding at the membrane through every thaw cycle. A quarter of the winter emergencies we see trace back to a strainer that ten minutes with a trash bag would have prevented. If your roof already holds water in places, read our ponding water page, because winter turns that nuisance into a weapon.

2. Seams and the field membrane. Walk the field in a grid and look down. On single-ply roofs, look for seam edges that are lifting, fishmouths (small open curls at a seam edge), and anything that catches your glove when you run it along a seam. On modified bitumen, look for surface cracking and bare spots where granules have gone. Freeze-thaw is a crowbar: any opening that exists in November will be wider by March, because water gets in, freezes, expands, and repeats forty times a winter. Small openings are maintenance items now and seam failures by spring. Photograph anything suspicious with something for scale.

3. Flashings, curbs, and penetrations. Now check everywhere the roof gets interrupted, which is where most leaks are born. At each rooftop unit, walk the curb and look for flashing that is pulling away, sealant that has cracked or shrunk, and gaps at corners. Check pipe boots for splits, pitch pockets for dried-out filler, and the parapet walls for loose coping and open mortar joints. Meltwater is patient and it finds every gap that summer rain missed, because it sits against details for days instead of minutes.

4. Edge metal and terminations. Walk the perimeter (carefully) and sight along the edge metal. Look for sections that are loose, lifted, or rattling in wind, and termination bars that have worked away from the wall. Winter wind events pull at the edge first, and an edge that is loose in November is the starting point for a peel.

5. Housekeeping and traffic damage. Clear all debris from the field: branches, bottles, whatever the year deposited. Check for punctures and scuffs along the routes trades walk, especially around HVAC units after service visits. If there are no walkway pads on those routes, put them on the spring list. Confirm the roof hatch closes and seals properly.

6. Look up from below. Inside the building, scan the deck and ceiling for new stains, and note anything on the top floor that smells musty. Interior evidence in November is a message from the roof, and it is far cheaper to answer now than in February.

Write down your snow plan now

Decide before the first storm: what snow depth triggers removal, who does it, and how. Chicago-area roofs are designed for normal snow loads, but drifted snow against parapets and equipment can locally triple the load, and a heavy wet storm followed by rain is the classic overload scenario. If removal is ever needed, it is plastic shovels only, never metal, working in a pattern that avoids piling snow, and leaving the last inch or two rather than scraping membrane. Ice dams at drains and freeze-thaw damage have their own page: our guide to winter flat roof damage covers what to watch between storms.

Between walks: what to watch all winter

The November walk sets the roof up; a few low-effort habits keep it honest through the season. After every significant thaw, check the drains from the roof hatch, because a thaw is when the season’s debris and refrozen slush make their move on the strainers, and a drain that fails in January stays failed until someone notices. After every major wind event, look at the roof edge from the ground on all four sides: lifted or rattling edge metal announces itself visually, and catching it before the next gust matters more than anything else on this list. Watch the scuppers and overflows during melts; strong flow means the primaries are doing their job, while a silent scupper on a roof full of melting snow means water is going somewhere else, and somewhere else is never good news.

Inside, make the top-floor ceiling part of somebody’s weekly route, and treat any new stain as a same-day report rather than a spring project, because winter leaks travel far from their source and grow while they wait. If a leak does show up mid-season, our flat roof leaking guide covers the triage steps in order. Fifteen minutes a month, mostly from the hatch and the ground, is the entire program, and it is the difference between a roof that gets through February and one that makes February memorable.

What the walk cannot tell you

An honest limit: this checklist finds surface problems, and surface condition is only half the story. What it cannot see is moisture already inside the assembly: wet insulation from an old leak, quietly killing R-value and rusting fasteners under a membrane that looks fine. That takes core samples and moisture readings. If your walk turns up multiple flags, or the roof is past its mid-teens, the right next step is a professional roof assessment: an estimator walks it within 48 hours of your request, cores it where the story is hiding, and emails you an itemized report with photos. Free, no sales calls, and if the roof just needs the maintenance items you already found, the report says exactly that.