What We Inspect and How
Seam integrity: We run a probe test on a representative sample of heat-welded seams, minimum one test per 400 linear feet of seam, plus every seam in a flashing transition zone, every seam within 12 inches of a penetration, and every T-junction where three membrane pieces meet. Probe testing catches cold welds that pass visual inspection and hold through the first season but fail under freeze-thaw cycling. On a St Louis commercial TPO installation, the freeze-thaw season is the seam stress test that distinguishes compliant welds from technically inadequate ones. We would rather find the cold weld before the manufacturer's inspector does.
Flashing details: Parapet walls, drains, penetrations, curbs, and expansion joints are each photographed against the manufacturer's published detail drawing for that transition type. St Louis buildings have above-average flashing failure rates at expansion joints and parapet transitions compared to Sun Belt markets because the thermal movement range the membrane sees between January lows and August highs is significantly larger. We apply additional attention to these transitions because they are where the St Louis manufacturer field representatives look first.
Fastener pattern: For mechanically attached systems, we inspect a sample of fastener patterns at the field, perimeter, and corner zones against the approved wind-uplift design. The derecho exposure in Missouri requires proper perimeter and corner zone fastener density, conditions we verify specifically on large open commercial roofs in Chesterfield, Hazelwood, and the industrial corridors where open-field wind exposure is highest.
Manufacturer Warranty Inspection Support
Major manufacturer warranty inspections for Carlisle, Versico, GAF, and Mule-Hide NDL systems are conducted by the manufacturer's field representative or credentialed inspector. The inspection produces a punch list of conditions that must be corrected within the manufacturer's cure window, typically 30 to 90 days, before the warranty is issued. Items that stay open past the cure window generate warranty suspension notices.
We support owners and general contractors through manufacturer inspections in two ways. Before the manufacturer's inspector arrives, we walk the roof and identify probable punch-list items so the installing contractor can correct them proactively. The conditions that generate St Louis warranty punch lists most consistently, parapet flashing seam shrinkage from freeze-thaw, drain ring under-torque, expansion joint cover displacement, are all correctable with less than a day of crew time if identified before the manufacturer visit. After the manufacturer's inspection, if a punch list is issued, we scope the remediation, execute it under the applicable manufacturer's repair standard, and submit the completion documentation.
Pre-inspection walks reduce punch list length and accelerate warranty issuance. On a Carlisle or Versico NDL inspection in this market, the difference between a two-item punch list and a twelve-item punch list is often a half-day of pre-inspection correction work.
Report Format and Deliverable
Every third-party QA inspection produces a written report within five business days of the field visit. The report includes: an executive summary with the count of warranty-jeopardizing, specification-deviation, and observation findings; a roof zone diagram with each finding keyed by number; a finding-by-finding detail section with photograph, location, description, applicable manufacturer requirement or specification citation, and recommended corrective action; and a findings matrix formatted as a spreadsheet that is sortable by zone, category, and priority level.
The findings matrix is designed to function as a contractor correction-required list. The installing contractor can assign items to crew, document completion, and return a remediation confirmation for each finding. For owners using the report for manufacturer warranty inspection support, the same document serves as the pre-inspection correction scope.
Timing of QA Inspection for Maximum Value
The highest-value inspection window is during installation, before the membrane covers the insulation, while seams and flashings are still fully accessible. An inspection at this stage can identify insulation specification deviations and deck conditions that would otherwise be concealed once the membrane is installed. When the inspection scope includes cover board verification, we conduct that portion of the inspection before the membrane installation phase begins.
Post-completion inspection, conducted after the full installation is complete, has a narrower scope but is still valuable for seam probe testing, visible flashing detail verification, and drain ring inspection. Conditions under a completed membrane require destructive investigation to assess, which changes the economics and the process. We advise clients on the optimal inspection timing based on the project schedule and the specific risk profile of the building. Buildings with critical occupied spaces below the roof or complex flashing geometry benefit most from mid-installation inspection visits.
QA Inspection for Post-Storm Repair Verification
After major storm events in the St Louis metro, commercial buildings commonly receive emergency and permanent repair work from contractors they may not have prior experience with. Post-storm demand spikes attract out-of-market contractors who may be unfamiliar with St Louis permit requirements, manufacturer detail standards, or the specific seam and flashing details that the Carlisle and Versico field representatives scrutinize during warranty inspections.
We conduct third-party QA inspections on post-storm repair work for building owners who want independent verification that emergency and permanent repairs were performed to manufacturer specification. This is particularly valuable for buildings with active NDL warranties where a non-compliant repair could void the warranty on the surrounding membrane field. The QA inspection confirms the repair was installed correctly, documents the materials used, and provides the owner with a record that supports the warranty's continued validity.
