First, describe the work and worksite
A roofing crew will mechanically fasten specified TPO membrane and heat-weld its laps on a released low-slope commercial roof. Deck, insulation and cover board have already been accepted for this system. This fictional learning example describes planned controls; it records no actual inspection or work authorization.
- The approved attachment layout, membrane, fasteners and welding criteria match the actual roof assembly.
- Edge/opening protection, roof-load limits, electrical supply and the site’s applicable hot-work/fire controls are established.
- EPDM adhesive seaming, PVC, induction attachment and installing insulation or cover board are excluded.
Questions before work
- What confirms fastener locations, deck suitability and perimeter details?
- How will welding settings be verified as conditions change?
- Where can a hot welder be parked without exposing people or materials?
Build the analysis one step at a time
What will the worker do? How could someone be harmed? What prevents or reduces that exposure? Who checks the control, and when?
1. Accept the roof assembly
Hazard: Unsuitable substrate or loading can cause falls, fastening failure or roof damage.
Control: Roofing lead confirms the released deck, insulation and attachment design. Walk the protected route, identify load limits and keep openings/edges controlled before membrane deliveries.
Verification: Lead compares the roof handover with the approved system details.
Why this belongs in the analysis: A membrane installation starts with its receiving assembly.
2. Stage and lay membrane
Hazard: Loose rolls or wind-lifted sheets can strike or pull workers toward an edge.
Control: Stage rolls within roof-load limits and secure materials against movement. Lay only the manageable area in the planned sequence, maintaining protected positions and clear escape/access routes.
Verification: Foreperson monitors wind and sheet control during rollout.
Why this belongs in the analysis: An unfastened sheet can become a large moving surface.
3. Install mechanical attachment
Hazard: Fasteners can strike concealed services or fail in an unsuitable deck.
Control: Use released fastening locations and the specified plates/fasteners and spacing. Follow the approved system installation and required substrate checks; stop for unexpected deck response instead of adding improvised fasteners.
Verification: Installer records the required attachment checks against current details.
Why this belongs in the analysis: The attachment design carries roof-system loads.
4. Set up and verify welding
Hazard: Hot air, electrical faults or incorrect settings can burn workers or produce defective seams.
Control: Inspect welder and supply, arrange safe hot-tool parking and fire controls, and make the system-required test weld. Evaluate it by the manufacturer’s cooling and acceptance method; repeat as required when conditions change.
Verification: Assigned welder records actual test results before production seams.
Why this belongs in the analysis: A dial setting from another roof is not a verified weld.
5. Weld and inspect laps
Hazard: A hot nozzle can burn workers; unchecked seams can remain open.
Control: Follow the actual system’s heat-welding method with people clear of the hot tool and cords. Allow the prescribed cooling, probe/test seams under its instructions and repair/recheck deficiencies before handover.
Verification: Welder and lead verify completed seams and identify unresolved areas.
Why this belongs in the analysis: Inspection timing matters because warm seams can be damaged.
6. Secure and hand over
Hazard: Hot equipment or unsecured membrane can expose the next crew.
Control: Complete required daily seam closeout, cool and secure welders and restrain unfinished work against weather. Communicate incomplete attachment, seams and roof restrictions to the receiving lead.
Verification: Foreperson records daily closeout and remaining actions.
Why this belongs in the analysis: The shift ends with both hot-tool and membrane controls.
What does a useful control look like?
| Needs improvement | More useful for this scenario |
|---|---|
| Work carefully and wear PPE. | Use released fastening locations and the specified plates/fasteners and spacing. Follow the approved system installation and required substrate checks; stop for unexpected deck response instead of adding improvised fasteners. |
| Check that everything is ready. | Roofing lead confirms the released deck, insulation and attachment design. Walk the protected route, identify load limits and keep openings/edges controlled before membrane deliveries. |
Decisions that change the analysis
Can the EPDM seam procedure be used for TPO?
No. This TPO system uses mechanical attachment and manufacturer-defined heat welds. EPDM adhesive and tape instructions do not establish TPO welding settings, cooling times or seam acceptance.
What must the crew record for actual use?
Identify the actual equipment and work boundaries, responsible people, applicable criteria, inspection findings and open actions. Resolve changes with affected crews and obtain required project authorization before work.
Agree when the crew will pause
- Failed test weld, changed conditions or recurring seam defects.
- Unexpected fastening response, deck/service uncertainty or system mismatch.
- Wind control, roof protection or hot-tool/electrical controls fail.
After a pause, correct the condition, reassess the work, and obtain required authorization before restarting. Keep unresolved actions visible.
Download the worked example and free template
No account or paid membership required. The worked example contains planned controls. The blank template is for your own work; neither includes fabricated inspection results, signatures or approval.
Your editable working copy
Build and download your draft
Start blank or load the learning example. Replace its assumptions with your actual conditions and involve the people doing the work. Your entries stay in this browser tab; download a copy before leaving or refreshing.
1. Describe your work and site
2. Work through each task
Describe an observable step, how someone could be harmed, and the control that acts on that hazard. Identify who checks it and what evidence is needed.
3. Record changes, checks, and open actions
Walk the work area, review with the crew, and resolve missing controls. Follow the required approval process. This tool does not judge completeness, verify signatures or authorize work.
Open the downloaded file in a browser, then use Print → Save as PDF for a printable copy.
Training needs to confirm
- System-specific mechanical attachment and demonstrated test-weld/seam-verification method.
- Roof fall/opening protection, electrical supply and safe hot-tool handling instruction.
Confirm applicable qualifications, task instruction and actual training evidence for the people assigned. Related toolbox talks support crew discussion; they do not establish competence.
Common questions
Can this example be used as a JSA?
Adapt its Task | Hazard | Control analysis to the employer’s format and actual conditions. The example is a teaching aid, not evidence that controls were checked.
What changes if the project requires an AHA?
Use the governing AHA format, risk method, supporting records and acceptance process. The published formwork AHA demonstrates that additional structure; changing a JHA title does not supply it.
Are these resources part of a paid course?
This walkthrough, browser draft builder and downloads are free public resources, separate from Academy course enrollment.
References and source note
- Carlisle Test welds and seam probing
- OSHA 1926.501 Duty to have fall protection
- OSHA 1926.404 Wiring design and protection
Original instructional scenario with planned controls. Primary references support hazard planning. Use actual equipment and product instructions, project design and employer requirements to establish field criteria. Use actual equipment instructions and site requirements alongside these references. Reference review: October 9, 2026.