PVC waterstop tape is the standard method for waterproofing construction and expansion joints in concrete structures. Choosing the right type, width and placement method is critical — the wrong specification can lead to leakage, structural damage and costly repairs. As a direct manufacturer with over 30 years of experience, Plast Commerce produces all four standard types (A, D, AE, DE) and provides free technical consultation for project-specific selection.
The Four Types of PVC Waterstop
Type A
CentreThe most common type. Placed in the centre of the concrete cross-section at construction joints where no movement is expected. The flat profile with anchor ribs provides reliable watertight seal.
Type D
Centre CompensatorFeatures a central bulb (compensator) that absorbs movement in expansion joints. Essential where thermal or structural movement is expected. The compensator can accommodate ±10–15 mm displacement.
Type AE
ExternalDesigned for external placement when access to the centre of the cross-section is not possible. One wing is cast into the first pour, the other into the second.
Type DE
External CompensatorCombines external placement with a compensator for expansion joints. Used where both movement accommodation and external mounting are required.
Width Selection by Water Pressure
The required width of waterstop depends on the hydrostatic pressure (water head) at the joint location:
| Water Pressure | Approx. Depth | Recommended Width | Typical Application |
|---|---|---|---|
| Up to 0.3 bar | Up to 3 m | 150–200 mm | Shallow foundations, basement walls |
| 0.3–0.5 bar | 3–5 m | 200 mm | Deep foundations, underground car parks |
| 0.5–1.0 bar | 5–10 m | 200–240 mm | Reservoirs, treatment plants |
| 1.0–2.5 bar | 10–25 m | 240–320 mm | Tunnels, dams, deep structures |
Centre vs External Placement
Centre Placement (Types A, D)
- ✓ More reliable — water must travel around both wings
- ✓ Better anchoring — fully embedded in concrete on both sides
- ✓ Preferred option when access allows
- ✗ Requires access to the centre of the cross-section
- ✗ Both concrete pours must be coordinated
External Placement (Types AE, DE)
- ✓ Can be installed when centre access is not possible
- ✓ Simpler installation in many configurations
- ✓ Often used in rehabilitation and retrofit projects
- ✗ Must be correctly oriented (water pressure side)
- ✗ One wing exposed until second pour
Installation Best Practices
Fix the waterstop securely in position before concreting — use tie wire or dedicated clips at 300–500 mm centres
Ensure minimum 100 mm concrete cover on each side of the strip
Weld joints with minimum 50 mm overlap using thermostatically controlled equipment at approximately 200°C
Clean joint surfaces thoroughly before welding — contaminants cause weak welds
Do not vibrate directly on the waterstop — vibrate on both sides to ensure proper concrete compaction
At T-junctions and corners, use pre-fabricated fittings or carefully weld custom intersections