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.
2. Advantages
- High mechanical resistance and elasticity; good elongation and tear resistance.
- Signal / contrasting layer available to reveal damage during installation (visual inspection)
- Durable and long service life when installed correctly (root and chemical resistance options exist).
- Weldable seams (automatic double-seam welding) enable pressure testing of joints in the field — reduces seam risk.
3. Limitations / Risks
- Loose-laid systems can allow lateral migration of water unless a fail-safe drainage / compartmentalization scheme is provided. Advanced Waterproofing_JLL_v1
- Membrane damage (punctures) during rebar work, pile heads, rock anchors or concreting is possible and must be patched rigorously. Advanced Waterproofing_JLL_v1
- Welding quality is critical — poorly welded laps are the main cause of failures. Requires trained welding operators and QA
4. Performance Parameters
Property | Test Method / Standard | Typical / Acceptable Range | Remarks |
Thickness (nominal) | EN 1849-2 / ASTM D751 | 1.5 mm – 2.0 mm | Ensure uniform thickness across sheet |
Tensile Strength | ASTM D412 / EN 12311-2 | ≥ 12–20 MPa | High mechanical strength to resist stresses |
Elongation at Break | ASTM D412 / EN 12311-2 | ≥ 150–300% | Indicates flexibility and crack-bridging |
Tear Resistance | ASTM D624 | ≥ 150 N | Resistance to mechanical damage during installation |
Puncture Resistance | ASTM F1306 | ≥ 400–500 N | Resistance to sharp aggregates / backfill pressure |
Peel Adhesion (lap joint) | ASTM D903 | ≥ 50–100 N / 50 mm | For welded seams, tested after welding |
Hydrostatic Pressure Resistance | ASTM D5385 / EN 1928 | ≥ 6 bar (60 m head) | No leakage under water pressure |
Dimensional Stability | EN 1107-2 | ≤ ±0.5% | Controls shrinkage / expansion |
Root Resistance (if required) | EN 13948 | Pass | For podium/landscaped areas |
Chemical Resistance | Manufacturer spec / EN 1847 | Pass in soil, chlorides, mild acids/alkalis | Should be certified |
Watertightness (sheet) | EN 1928 / IS 15351 | No leakage under specified pressure | Essential property |
Service Life Expectancy | Manufacturer declaration | 10–20 years (with correct detailing & protection) | Depends on QA/QC, execution, detailing |
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
- Prepare PCC: level, clean, free of laitance, sharp edges and standing water. Repair honeycombs and voids.
- Install geotextile cushion over PCC where specified (protects membrane during concrete placement).
B. Membrane placement & welding
- 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).
- 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.
- 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
- 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.
- Pile heads: reprofile pile head, dress membrane around pile head, weld and encapsulate with epoxy grout as per detail.
D. Protection & backfill
- Lay top geotextile/protection layer and minimum 50 mm cement screed (or protection board where necessary). Protect membrane from damage during reinforcement / concreting.
- Follow protection board and CLSM/backfill sequence as specified after installation and testing.
E. Repairs & documentation
- 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.