Flat & Low-Slope Roofing in Chicagoland & Southern Wisconsin

Not every flat roofing job is a commercial building. Many homes in Chicagoland have flat or low-slope sections: a detached garage, an addition built off the back of the house, a sunroom, or a low-slope transition connecting two roof planes. These sections fail differently than pitched roofing and need a contractor who understands the specific installation requirements for low-slope residential work.

Flat garage roofs are one of the most common residential flat roofing calls we receive. EPDM and modified bitumen are the most frequent specifications for detached garages: both are well-suited to the scale, handle temperature cycling reliably, and last 20–30 years when installed correctly. Poor drainage is the most common cause of premature failure. We assess the deck condition, correct any drainage issues, and install the right system for the structure.

When a home addition or sunroom is built with a flat or low-slope roof, the junction between the flat section and the existing pitched roof is a critical flashing point. Water management at that transition determines whether the addition stays dry for 20 years or becomes a chronic leak problem within five. Lakeland handles both the membrane installation and the transition flashing as a complete scope, not two separate jobs.

Whether you’re roofing a new commercial build or replacing a system at end of life, Lakeland handles the full scope: tear-off (where required), deck inspection and remediation, insulation, membrane, flashing, drainage, and coping. Every installation is documented and submitted to the manufacturer for warranty registration before final invoice.

Flat roof failures don’t wait for business hours. Lakeland provides commercial flat roof repairs for leaks, seam failures, flashing separations, and storm damage. For active leaks causing business disruption, we respond with emergency tarping and temporary protection to limit interior damage while permanent repairs are scheduled.

For flat roofs that are structurally sound but losing performance, a coating system can extend service life by 10–15 years at a fraction of replacement cost. Coatings also improve energy performance through reflective surface treatments. Lakeland evaluates coating eligibility as part of every commercial assessment.

TPO (Thermoplastic Polyolefin) is the most widely specified single-ply commercial roofing membrane for good reason: it performs well in both heat and cold, reflects UV radiation to reduce cooling loads, and when installed correctly — with heat-welded seams — delivers watertight performance for decades.

EPDM (Ethylene Propylene Diene Monomer) is a synthetic rubber membrane with a long track record on commercial and industrial roofs. It’s particularly well-suited to large roof areas, extreme temperature swings, and buildings where long-term low-maintenance performance is the priority.

PVC (Polyvinyl Chloride) membrane roofing offers excellent chemical resistance and is a strong choice for commercial kitchens, food processing facilities, and properties with rooftop equipment that exhausts grease or chemicals. Like TPO, PVC seams are heat-welded, producing a monolithic waterproof surface across the full roof plane.

Modified bitumen is a multi-ply asphalt-based system that delivers the redundancy of built-up roofing in a more efficient installation format. It performs well on roofs with heavy foot traffic or mechanical equipment exposure, and is commonly used for re-roofing over existing substrates where a full tear-off isn’t warranted.

Built-up roofing — alternating layers of bitumen and reinforcing fabric — is one of the most proven commercial roofing systems available. BUR excels in durability, redundancy, and fire resistance, and remains the specification of choice for certain property types and building codes. Lakeland’s commercial team has decades of experience with BUR installations on both new construction and replacement projects.