Bentonite-Based, Hydrophilic, Expandable, Flexible Rubber Waterstop Strip for Watertight Construction Idrostop B25 is a waterstop used to produce watertight construction joints in civil, industrial and hydraulic construction. Idrostop B25 is composed of a mix of natural sodium bentonite and polymers that give the product exceptional properties of compactness, flexibility and stability. The material is produced according to a formula developed in MAPEI’s own research and development laboratories. Idrostop B25’s expanding process takes place in a controlled, gradual and uniform way without the risk of altering the balance of the mix.

• Pre-formed flexible strip that features a bentonite base specially designed to form watertight construction joints
• When expanding upon contact with water, Idrostop B25 adapts perfectly to the volume defined by the surrounding boundaries
• Expands gradually in permanent contact with water, creating an active barrier against positive and negative water pressure
• Able to perfectly seal the formation of localized honeycomb voids that are present in concrete
• Stable at temperatures between -22°F and 122°F (-30°C and 50°C)