Chicago winters are among the most demanding environments for commercial roofing systems in the country. With average winter temperatures hovering in the 20s, frequent freeze-thaw cycles, heavy snowfall that can exceed 36 inches in a season, and sustained winds off Lake Michigan, commercial roofs in the Midwest endure months of punishing conditions every year. The difference between a roof that survives winter intact and one that fails with leaks and structural concerns is almost always the maintenance and preparation that happens in the fall.
At Windward Roofing & Construction, we have spent more than 40 winters maintaining and repairing commercial roofs across Illinois, Wisconsin, Michigan, and Indiana. This guide shares the essential steps every property owner and facility manager should take before winter arrives.
Schedule a Professional Pre-Winter Roof Inspection
The foundation of winter preparedness is a thorough professional inspection conducted in September or October, while the weather still permits repairs. A qualified roofing contractor will perform a comprehensive roof inspection, examining every component of the roof system, identifying vulnerabilities that could become serious problems under winter stress. The inspection should cover the membrane or roofing surface for splits, cracks, blisters, and open seams. It should evaluate all flashings around parapet walls, penetrations, HVAC equipment curbs, and roof edges. Sealants and caulking at terminations and detail areas should be checked for deterioration. The inspector should also assess the condition of all drainage components and check for evidence of ponding water, which indicates drainage deficiencies that will compound with snow and ice accumulation.
Do not wait until November or December to schedule this inspection. By that time, early winter weather may already be creating access challenges, and your contractor's schedule will be packed with emergency calls from property owners who did not plan ahead.
Clear and Maintain All Drains, Gutters, and Scuppers
Blocked drainage is the single most common cause of winter roof damage on commercial buildings. When drains, gutters, and scuppers are clogged with leaves, debris, or sediment, water cannot exit the roof. As temperatures drop, standing water freezes, expands, and creates enormous stress on the membrane and flashing details. It also adds dead weight that can exceed the roof's structural load capacity when combined with snow accumulation.
Before winter, every drain on the roof should be cleared of debris, inspected for proper function, and fitted with strainers to prevent clogging during the season. Interior drain lines should be checked for blockages or slow drainage. Gutters and downspouts should be cleaned, reattached where loose, and confirmed to direct water away from the building foundation. Scuppers and overflow drains should be verified as clear and functional. This is not a one-time task; ideally, drainage should be checked again in mid-winter during a thaw period to confirm ongoing function.
Understand and Plan for Snow Load
Commercial flat roofs in the Chicago area must be designed to support specific snow loads as required by building codes. However, actual snow loads during severe winters can approach or exceed design limits, particularly in areas where drifting occurs. Snow that drifts against parapet walls, mechanical equipment screens, and higher adjacent roof sections creates concentrated loads that can be two to three times the load on open roof areas.
Property owners should know their building's design snow load capacity, which can typically be found in the original building plans or obtained from a structural engineer. When accumulation approaches 50 to 75 percent of this capacity, proactive snow removal should be considered. Windward Roofing provides emergency snow removal services using crews experienced in working on commercial roof membranes without causing damage. Never allow untrained staff to shovel a flat roof, as metal shovels, ice picks, and improper techniques can puncture the membrane and create leak points that worsen the situation.
Prevent Ice Dams Before They Form
Ice dams are a persistent threat to commercial roofs in the Midwest. They form when heat loss from the building warms the roof surface enough to melt accumulated snow. The meltwater flows toward the roof edge, where colder temperatures cause it to refreeze. Over time, a ridge of ice builds along the roof perimeter, trapping water behind it. This trapped water can work its way under the roofing membrane, through flashings, and into the building interior, causing significant damage to insulation, ceilings, inventory, and equipment.
The most effective defense against ice dams is proper insulation and, where applicable, ventilation. Adequate insulation reduces the amount of heat escaping through the roof deck, keeping the roof surface closer to ambient temperature and preventing the melt-refreeze cycle that creates ice dams. During your fall inspection, have your roofing contractor evaluate insulation performance, particularly in areas where interior heat sources like boiler rooms or kitchens are located directly below the roof. Addressing insulation deficiencies before winter is far less expensive than repairing the water damage that ice dams cause.
Develop a Winter Emergency Plan
Even with thorough preparation, severe weather events can overwhelm a roof system. Having a winter emergency plan in place before you need it reduces response time and limits damage. Your plan should include the contact information for your roofing contractor's emergency line. Windward Roofing provides 24/7 emergency response for exactly these situations. Keep a list of your building's utility shutoffs in case interior flooding occurs. Identify a qualified snow removal contractor and have a service agreement in place before winter. Ensure building maintenance staff know how to safely access the roof and recognize signs of structural stress, such as sagging decking, cracking walls, or doors that suddenly stick.
Communication is also critical. Make sure tenants and building occupants know who to contact if they observe leaks, ceiling discoloration, or unusual sounds from the roof structure during heavy snow or ice events.
Why Fall Maintenance Matters
The cost of a professional fall inspection and any necessary repairs is a fraction of what emergency winter repairs, interior damage remediation, and business interruption will cost if a preventable failure occurs. Windward Roofing regularly sees the consequences of deferred maintenance: collapsed ceilings from ponding water frozen over blocked drains, extensive membrane damage from ice dam infiltration, and structural steel corrosion from years of undetected moisture intrusion. These are expensive, disruptive problems that are almost entirely preventable with proactive fall maintenance.
Midwest-Specific Challenges
The Midwest presents a unique combination of roofing challenges that property owners in milder climates never face. Freeze-thaw cycles, where temperatures cross the 32-degree threshold dozens of times per season, cause repeated expansion and contraction of roofing materials and water trapped in membrane imperfections. Lake-effect snow can deliver concentrated, heavy snowfall that exceeds seasonal averages in hours rather than weeks. Wind-driven rain and sleet can find their way into seam and flashing details that would remain watertight in calmer conditions. Extended periods of sub-zero temperatures stress every component of the roof assembly.
These conditions demand roofing systems that are properly installed by experienced contractors and diligently maintained throughout their service life. A roof that is adequate in a mild climate may be insufficient for Chicago, Milwaukee, or Detroit. Windward Roofing specifies and installs systems engineered for Midwest conditions and provides maintenance programs designed to keep them performing through the toughest winters.
Do not wait for the first snowfall to think about your roof. Contact Windward Roofing today to schedule a pre-winter inspection and make sure your commercial building is ready for whatever this winter brings.
Frequently Asked Questions
Most commercial flat roofs are designed to support a minimum of 20 pounds per square foot of snow load, though this varies by building code, location, and structural design. In the Chicago area, building codes typically require commercial roofs to support 25 to 30 pounds per square foot. One foot of fresh snow weighs approximately 5 to 10 pounds per square foot, while wet, packed snow can weigh 15 to 20 pounds per square foot. Always consult your building's structural engineer for specific load capacities.
Schedule your pre-winter roof inspection in September or October, before the first freeze. This gives your roofing contractor enough time to identify issues and complete any necessary repairs while weather conditions are still favorable for roofing work. Waiting until November or December risks delays from early winter weather and limits the types of repairs that can be performed.
Ice dams form when heat escaping from the building melts snow on the roof surface. The meltwater flows toward the colder roof edges and gutters where it refreezes, creating a dam of ice that blocks further drainage. Water pools behind the dam and can back up under the roofing membrane, causing leaks and interior damage. Poor insulation, inadequate ventilation, and blocked drains are the primary contributing factors.
Snow removal is recommended when accumulation approaches your roof's structural load capacity, when drifting creates concentrated loads near parapet walls or mechanical equipment, or when drains are buried and unable to handle meltwater. Always use experienced professionals for commercial snow removal, as improper techniques can damage the roofing membrane. Never allow untrained personnel to shovel or use sharp tools on the roof surface.