Flat roofs are common on Milwaukee additions, commercial buildings, and older bungalow-style homes. The two dominant membrane systems in Wisconsin's market are TPO (Thermoplastic Polyolefin) and EPDM (Ethylene Propylene Diene Monomer). They're both single-ply systems, both appropriate for Wisconsin's climate, but they perform differently in practice.
TPO
TPO is heat-welded at the seams, creating a chemically bonded joint that's stronger than any adhesive system. It's white or light gray by default, which reflects UV and reduces cooling costs on commercial buildings. Milwaukee commercial installations: $5.50–$8.50/sq. ft. installed.
Weakness: TPO formulations have historically varied in quality — early-generation TPO from the 2000s had premature cracking problems. Modern TPO from established manufacturers (Firestone, GAF, Carlisle) is significantly more durable. Always ask for the generation and manufacturer.
EPDM
EPDM is the black rubber membrane — most visible on residential flat roofs and additions in Milwaukee. It's installed with adhesive, tape, or ballasted (loose-laid and held down by gravel). Adhesive-set seams are the weak point; ballasted systems perform better long-term but add 10–12 lbs/sq. ft. of load.
EPDM is more flexible in cold temperatures, which matters during Milwaukee's winter installations. TPO becomes stiffer in cold and is harder to heat-weld below 40°F. For emergency winter flat roof replacements, EPDM is often the practical choice.
Milwaukee residential EPDM installation: $4.50–$7.00/sq. ft.
Which One for Milwaukee?
Commercial buildings: TPO, for the reflective surface and welded seams.
Residential additions and low-slope sections: EPDM with adhesive seams, properly lapped and sealed.
Both systems carry 15–20 year warranties when installed by certified contractors.
Apexium Roofing installs both systems and will recommend based on your specific building, slope, and drainage situation — not what's cheapest to install.
Have a specific question about your Milwaukee roof? We answer directly.