PVC Sheet Membrane Waterproofing

1. Introduction

PVC (polyvinyl chloride) sheet membranes are flexible thermoplastic waterproofing sheets used extensively for below-grade tanking and roof/podium membranes. For basements, PVC membranes are typically loose-laid or partially bonded over a geotextile/underlay, welded at laps and covered with a protection screed or geotextile. PVC systems allow automatic double-seam welding and can be pressure-tested during installation for seam integrity.

4. Performance Parameters

5. Recommended Use Cases

• Deep / large basements with high water table and structural movements
• Raft slabs where a loosely-laid membrane over PCC with protection screed is acceptable (large excavation, heavy construction equipment).
• Retaining walls (vertical membranes) when shore piles / D-walls are dressed and membrane can be fixed before casting.

6. Application Steps — PVC Tanking

A. Substrate & pre-works

1. Prepare PCC: level, clean, free of laitance, sharp edges and standing water. Repair honeycombs and voids.
2. Install geotextile cushion over PCC where specified (protects membrane during concrete placement).

B. Membrane placement & welding

1. Lay PVC membrane rolls over geotextile; align panels and prepare for welding. Typical below-grade thickness used: 1.5–2.0 mm (2.0 mm common for large basements).
2. Weld laps using automatic double-seam welding machines for main joints (450–550°C typical welding temp range referenced in BASF deck for automatic welding); use hot-air/hand welding for corners, complex details and repairs.
3. Pressure-test double welds (compartmentalize raft if needed) — double seam pressure testing possible during execution; single seams can be checked with a seam probe.

C. Detailing at penetrations & sleeves

1. Rock anchors / PRP sleeves: cut membrane as required, weld patch pieces, install hydro-swelling paste (where specified), epoxy encapsulate anchor heads and finish with sealant. Follow sequence: cut → weld → swelling paste layers → tighten clips → epoxy encapsulation.
2. Pile heads: reprofile pile head, dress membrane around pile head, weld and encapsulate with epoxy grout as per detail.

D. Protection & backfill

1. Lay top geotextile/protection layer and minimum 50 mm cement screed (or protection board where necessary). Protect membrane from damage during reinforcement / concreting.
2. Follow protection board and CLSM/backfill sequence as specified after installation and testing.

E. Repairs & documentation

1. Inspect all seams and welds; patch defects with welded patches ≥150 mm overlap; record all patch locations on as-built drawing

F. Special Execution Notes

• Compartmentalization: use waterstops/compartment joints so any future leakage is localised and repairable.
• Automatic welding + seam pressure testing: double welds enable pressure testing of welded joints; single seam testing can be done using a seam probe.
• Signal Layer: membranes with a contrasting signal layer help detect damage during installation.

6. Section Drawings

• Raft (PCC → geotextile → PVC membrane → geotextile/protection → screed → RCC). Advanced Waterproofing_JLL_v1
• Vertical retaining wall / shore pile detail with vertical membrane and casting sequence. Advanced Waterproofing_JLL_v1
• Rock anchor / PRP sleeve detail showing swelling paste, welded patch, epoxy encapsulation.

7. Inspection & ITP

• Material acceptance: supplier TCs, batch numbers, thickness check on roll sample.
• Pre-weld checks: panel alignment, cleanliness, substrate, geotextile. Advanced Waterproofing_JLL_v1
• Weld quality: automatic weld log, welder operator qualification, seam probe tests (single seam) and pressure test (double seam compartments). Advanced Waterproofing_JLL_v1
• Completed work tests: random destructive tests on sample welds, water tightness / hydrostatic tests on compartments where possible, visual inspection and as-built records. Advanced Waterproofing_JLL_v1
• Sampling frequency: define per project (example: one welded seam test per X m or per roll junction; one material property test per site batch — align with project QA).

8. Reference Standards

• ASTM D4434 — Specification for PVC Roof Membrane (useful for material property guidance).
• EN 13967 — Flexible sheets for waterproofing (below-grade: waterproofing sheets for foundations/basements).
• EN 12311-2 — Tensile properties test methods for thermoplastic sheets (refer to EAD/EN test procedures).
• EN 1928 / EN 12311 — Watertightness & mechanical testing procedures for sheets.
• IS 15351 / national standards where applicable (for regional compliance).
• Project drawing and manufacturer’s datasheet are the final authority for acceptance values

9. Documents

Specifications, BOQ, and Checklist

5. Video Masterclass

SpecX Masterclass: PVC Sheet Membrane Waterproofing — Coming Soon

Disclaimer

SpecX is an industry initiative & a neutral resource, compiled from industry references and best practices. It is not brand-specific. Always cross-check with project requirements and local codes before finalizing specifications.