What has to be measured before fabrication?
We record roof dimensions, slopes, parapets, curbs, pipe locations, drains, scuppers, and edge transitions. A measurement error can shift a seam or place an accessory where it cannot fit cleanly. We confirm field conditions against plans and identify later changes by mechanical or electrical trades. The roof survey also looks for prior patches, unusual transitions, and sections where the deck or insulation may need repair before new membrane is laid.
The existing roof determines demolition and substrate work. We inspect for moisture, loose board, uneven surfaces, and incompatible material at tie-ins. If the proposal includes a recover, the assembly must allow the existing layers to remain. If tear-off is required, the bid sets limits and an allowance for concealed deck repairs. Those decisions should be made before the custom material order is released. We coordinate the equipment and curb schedule so fabricated pieces match the final opening, not a temporary dimension from an outdated drawing.
How does Duro-Last fabrication change field work?
Duro-Last states that its PVC membrane system can be custom fabricated with factory-welded seams and custom-fabricated accessories. The intended benefit is to move selected seam and transition work into controlled fabrication, while the project still requires field seams and connections to be completed correctly. We identify the prefabricated sections and accessories in the scope, verify dimensions, and mark where the field tie-ins remain. The proposal should not imply that all details arrive finished or eliminate on-roof quality checks.
Once delivered, the pieces need to be staged and matched to the roof plan. We confirm the layout, protect the membrane from damage, and check each opening before the crew closes the assembly. At a curb, the accessory must fit the actual curb and integrate with the field membrane. At drains and scuppers, the membrane turn-down and flange detail must align with the drain body. The general contractor can help by freezing equipment locations and communicating any late changes before fabrication is complete.
Which field connections still require close inspection?
Factory work reduces some field seams, but the roof still has transitions at parapets, expansion joints, curbs, pipes, and drains. Those connections must be integrated with the installed sheet and compatible accessories. We inspect membrane laps, welded edges, terminations, and flashing corners before they are covered. A wrinkle or open edge around one penetration can let water travel below a much larger panel, so we trace the repair boundary instead of sealing only the visible drip point.
When a repair is needed, we identify the membrane and the reason for failure. A puncture, failed lap, loose termination, or wet substrate calls for a different repair scope. We remove compromised material, prepare a dry and sound surface, and install a compatible patch or detail. We record any remaining deck or insulation concern separately. This gives the owner a useful baseline for later inspection and avoids treating the top sheet as the only component that can fail.
How does Antioch affect delivery and dry-in?
Antioch's July mean daily maximum is 91.1 degrees F. For a custom-fabricated reroof, the crew still needs a practical plan for unloading, rooftop staging, shade or heat precautions, and membrane protection. Cooler-season precipitation makes the daily work boundary just as important. A January 2019 report at Antioch 2.2 WSW recorded 2.46 inches over 48 hours; the event is a historical local reference, not a forecast. We plan each shift around current conditions and the roof's drain capacity.
The Eastern Waterfront planning area includes light-industrial uses such as enclosed fabrication, assembly, and packaging; Rivertown includes multiple commercial blocks. The property manager sets the access schedule for the actual building. If a rooftop HVAC unit will be replaced, its curb dimensions and delivery window need to be resolved before the membrane is fabricated. A changed opening after delivery may require additional field work, a new transition, or a revised tie-in plan.
What should the owner receive after installation?
The project file should include the final roof plan, field measurements, selected Duro-Last product documentation, submittals, and photographs of concealed transitions. We record the actual location of seams and accessories, the repair of any deck opening, and the final condition of drains, edges, and curbs. The closeout also lists work by other trades that still needs inspection. That record is useful when a later service call involves a new penetration or a leak near a fabricated transition.
After turnover, keep drains clear and restrict unplanned traffic around sensitive details. Coordinate rooftop work before new equipment or supports are installed. A routine commercial roof inspection can document changes and identify a repair boundary while the condition is still visible. Owners can also compare future capital choices through a roof capital plan. For immediate water entry, we can establish a temporary water stop and then define the permanent repair scope.
When another single-ply product is under consideration, compare how much work is fabricated before delivery and what still has to be built on the roof. Sika Sarnafil's PVC membrane options and SOPREMA's SENTINEL PVC system use their own sheet layouts and accessory details. For Duro-Last, confirm the measured opening dimensions, custom pieces, field tie-ins, and edge conditions against the final roof plan. This keeps the material order connected to real curb and drain locations. Any late equipment change should be reviewed before fabrication or assigned a documented field detail.
The survey should capture each change in roof plane, including inside and outside corners where a fabricated section meets field membrane. We compare dimensions against the latest equipment schedule and confirm that drains, scuppers, and overflow routes remain accessible. If a curb moves, the project team needs to resolve the revised opening before the membrane is installed. A documented change avoids forcing the crew to stretch a fabricated piece or improvise a detail that was never part of the approved scope.
Commercial Roofing Questions
What does custom fabrication change on a Duro-Last roof?
Selected membrane sheets and accessories can be fabricated to measured roof conditions. Field tie-ins and transitions still require careful installation and inspection.
When should roof measurements be confirmed?
Confirm dimensions, curb locations, drains, and any equipment changes before fabrication. Late changes can affect accessory fit and the field-seam plan.
Can Duro-Last be installed over an existing roof?
That depends on the existing layers, moisture, substrate, and approved assembly. We inspect the roof and confirm the recover scope before recommending it.
Do factory-welded sheets eliminate field seams?
No. Fabrication can reduce selected on-site seams, while field connections remain at roof edges, openings, drains, and tie-ins.
What should the building team protect after turnover?
Keep drains clear and coordinate future rooftop work before cutting or fastening through the membrane. Record each new curb or penetration for inspection.
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