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CS-235 Rapid Expansion Waterstop Sealant

For concrete joints in: Building Foundations, Slabs, Retaining Walls, Storage Tanks, and similar Non-Moving, Cold, Construction Joints. Not intended for use in expansion joints or joints that move.

NSF Standard 61 Certified, Safe for Drinking Water Applications


  • Always use an appropriate ConSeal primer product to avoid displacement of CS-235 during the concrete pouring. It may be necessary to utilize masonry nails or other mechanical means to hold the sealant in place on vertical surfaces
  • Place CS-235 waterstop so that it is no closer than 2” away from the outer surface of poured structure. If a keyway is utilized, place the CS-235 into the bottom of the formed keyway area

ConSeal CS-235 waterstop is a unique sealing compound designed to expand rapidly when exposed to moisture, making it a self-healing joint material for construction joint applications.

Physical Properties

Description Spec CS-235
Color: Black
Specific Gravity: ASTM D71 1.40 ± 5
Hydrocarbon Content: ASTM D4 47% min.
Volatile Matter: ASTM D6 1% max.
Penetration, cone 77°F, 150 gm. 5 sec.: ASTM D217 43 – 46 dmm
Application Temperature Range: -10°F to 125°F (-22°C to 52°C)
Service Temperature Range: -30°F to 180°F (-34°C to 82°C)

Performance Characteristics

Description CS-235
Maximum Swelling – Freshwater: 250%
Maximum Swelling – Saltwater (3%): 35%
Hydrostatic Pressure Resistance

     Standard Precast Concrete Joint:


30 psi (2 bars)

     Cast-In-Place Construction Joint: 100 psi (6.8 bars)

Immersion Testing

Freshwater Exposure Results:

24 Hours:     60% Expansion

72 Hours:     100% Expansion

7 Days:         150% Expansion

14 Days:       175% Expansion

21 Days:       200% Expansion

30 Days:       225% Expansion