TPO (Thermoplastic Polyolefin) is the most specified commercial flat roofing system in Milwaukee County. Here's what property managers and building owners should know before a TPO installation.
How TPO is Installed
TPO comes in rolls — 10, 12, and 20 feet wide. Sheets are adhered to the insulation layer (typically polyiso) with bonding adhesive or mechanically fastened, then overlapped and heat-welded at the seams.
The heat-welding process is where quality separates itself. Proper seam welds require a commercial hot-air welding machine set to the correct temperature for the ambient conditions and the specific TPO product being installed. Under-welded seams peel within 2–5 years. The seam width should be a minimum of 1.5 inches of fused material — verifiable with a seam probe after installation.
Drainage: The Most Critical Design Element
TPO extends flat roof life — but only if drainage is engineered correctly. Milwaukee commercial buildings often have inadequate drain placement from original construction. Standing water on a TPO roof accelerates membrane degradation and adds structural load.
Before any TPO installation, Apexium assesses existing drain locations, slope, and ponding history. We recommend drain additions or tapered insulation if existing drainage is insufficient.
Warranty Options
TPO warranties range from 10 to 30 years depending on manufacturer, membrane thickness (60 mil vs. 80 mil), and installer certification level. Apexium is certified by Firestone and GAF — both offer 20-year no-dollar-limit warranties on qualifying installations, which include labor and material coverage if a defect produces a leak.
What to Watch During Installation
Attend or have a representative present for the seam welding inspection. Check: seam probe testing is being performed, all penetration flashings are fully adhered and terminated, drain sumps are set below the membrane surface (not flush or above).
Contact Apexium for a commercial TPO estimate and drainage assessment.
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