Verified Workflow

A concise, field-proven sequence for installing thermoplastic PVC waterproofing by hot-air/hot-wedge welding. Use alongside project specifications and the manufacturer’s TDS. Confirm parameters with on-site trial seams and record approved settings before production work.

Guide

1. Define the system: PVC membrane type, thickness, and attachment method (mechanically fastened, fully adhered, or loose-laid under ballast), plus compatible accessories. Consider UV exposure, temperature range, potential water head, and expected substrate movement.

2. Plan sheet layout and details: roll direction, lap width, and welding sequence. Document terminations, penetrations, movement joints, and drainage elements in the working drawings.

3. Prepare the substrate: ensure evenness, cleanliness, and dryness with no sharp edges. Install separation/protection layers and, where required, a vapor barrier according to the design.

4. Receive and store materials correctly: verify roll labels and quality documents. Store on pallets, protected from moisture and direct sunlight. Avoid edge deformation.

5. Set up welding equipment: make trial seams with hot-air or hot-wedge welding. Tune temperature, travel speed, and pressure on samples. Record the approved parameters.

6. Unroll and position sheets without folds or internal tension. Form the specified lap. Keep the future seam zone clean and dry. Use temporary fixation where wind/slope requires.

7. Weld longitudinal seams with stable parameters, controlling heat input and nip pressure. Close T-joints with reinforcing T-patches per the manufacturer’s instruction.

8. Form transverse seams and details (terminations, corners, drains) in the prescribed sequence. Avoid overheating or scorching. Maintain uniform roller pressure.

9. Perform non-destructive testing of seams: for dual-track seams, air-channel pressure testing. For single seams, vacuum box testing with soap solution on representative lengths.

10. Conduct periodic destructive tests: peel and shear specimens taken from control areas. Compare results with TDS requirements and adjust welding settings if deviations occur.

11. Install details and finishes: penetrations, parapets, edges with pressure bars, sealants, and water-cutoff features. Use protection angles and local reinforcements where stress concentrations are expected.

12. Lay protection and drainage layers on horizontal and vertical areas as designed. Ensure continuity of the drainage path and correct water discharge.

13. Place ballast/overburden or service layers without impact or shear on the membrane. Use inert materials free of sharp inclusions. Control layer-by-layer compaction.

14. Maintain documentation and environmental controls: seam maps, welding logs, and inspection records. Observe limits for temperature, wind, and precipitation. Mitigate dew/condensation with covers and localized preheating.

15. Enforce safety: PPE for hot-air welding and cutting, and ventilation in confined spaces. Maintain electrical safety of equipment and orderly routing of power cords and extensions.